← Product Code [QOF](/submissions/MI/subpart-d%E2%80%94serological-reagents/QOF) · K241240

# Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay (K241240)

_Hologic, Inc. · QOF · Jul 18, 2024 · Microbiology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/QOF/K241240

## Device Facts

- **Applicant:** Hologic, Inc.
- **Product Code:** [QOF](/submissions/MI/subpart-d%E2%80%94serological-reagents/QOF.md)
- **Decision Date:** Jul 18, 2024
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.3981
- **Device Class:** Class 2
- **Review Panel:** Microbiology

## Indications for Use

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) swab specimens and anterior nasal (AN) swab specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections. Nucleic acids from the viral organisms identified by this test are generally detectable in NP and AN swab specimens during the acute phase of infection. The detection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infection are indicative of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions. Positive results do not rule out coinfection with other organisms. The organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system. The Hologic RespDirect Collection Kit is cleared for NP swab specimens only for testing with the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay.

## Device Story

Fully automated multiplexed real-time RT-PCR assay for detection of SARS-CoV-2, Flu A, Flu B, and RSV. Input: nasopharyngeal or anterior nasal swab specimens in transport media. Process: automated nucleic acid extraction, purification, and multiplex RT-PCR amplification on Panther Fusion system. Output: qualitative detection results and cycle threshold (Ct) values. Used in clinical laboratories by professional users. Includes Adaptive Crosstalk Correction (ACC) in software to prevent false Flu B positives in high-titer SARS-CoV-2 samples. Results aid differential diagnosis alongside clinical/epidemiological data.

## Clinical Evidence

Prospective multicenter study (n=1,268) of symptomatic individuals; 1,189 evaluable AN swab specimens. SARS-CoV-2 performance compared to composite comparator algorithm; Flu A/B/RSV compared to FDA-cleared molecular assay. PPA/NPA for SARS-CoV-2: 94.8%/98.8%; Flu A: 91.8%/99.6%; Flu B: 66.7%/99.7%; RSV: 94.4%/99.8%. Retrospective study (n=175) supplemented low-prevalence Flu B/RSV data, showing high PPA (97.2-98.0%) and NPA (99.2-100%).

## Technological Characteristics

Multiplex real-time RT-PCR; automated nucleic acid extraction using magnetic particles. Targets: SARS-CoV-2 (ORF1ab), Flu A (Matrix), Flu B (Matrix), RSV (Matrix). Fluorophores: ROX (SARS-CoV-2), FAM (Flu A), HEX (RSV), RED647 (Flu B). System: Panther Fusion (software v7.2.7/7.2.9). Connectivity: Standalone instrument. Sterilization: N/A (reagents).

## Regulatory Identification

A device to detect and identify nucleic acid targets in respiratory specimens from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-target test is an in vitro diagnostic device intended for the detection and identification of SARS-CoV-2 and other microbial agents when in a multi-target test in human clinical respiratory specimens from patients suspected of respiratory infection who are at risk for exposure or who may have been exposed to these agents. The device is intended to aid in the diagnosis of respiratory infection in conjunction with other clinical, epidemiologic, and laboratory data or other risk factors.

## Special Controls

*Classification.* Class II (special controls). The special controls for this device are:(1) The intended use in the labeling required under § 809.10 of this chapter must include a description of the following: Analytes and targets the device detects and identifies, the specimen types tested, the results provided to the user, the clinical indications for which the test is to be used, the specific intended population(s), the intended use locations including testing location(s) where the device is to be used (if applicable), and other conditions of use as appropriate.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed descriptions of the performance characteristics of the device for each specimen type claimed in the intended use based on analytical studies including the following, as applicable: Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, precision, reproducibility, and clinical studies;
(iii) Detailed descriptions of the test procedure(s), the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) A warning statement that viral culture should not be attempted in cases of positive results for SARS-CoV-2 and/or any similar microbial agents unless a facility with an appropriate level of laboratory biosafety (
*e.g.,* BSL 3 and BSL 3+, etc.) is available to receive and culture specimens; and(v) A prominent statement that device performance has not been established for specimens collected from individuals not identified in the intended use population (
*e.g.,* when applicable, that device performance has not been established in individuals without signs or symptoms of respiratory infection).(vi) Limiting statements that indicate that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) There is a risk of incorrect results due to the presence of nucleic acid sequence variants in the targeted pathogens;
(D) That positive and negative predictive values are highly dependent on prevalence;
(E) Accurate results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(F) When applicable (
*e.g.,* recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer-reviewed literature), that the clinical performance may be affected by testing a specific clinical subpopulation or for a specific claimed specimen type.(4) Design verification and validation must include:
(i) Detailed documentation, including performance results, from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, as appropriate, additional characterized clinical samples. The clinical study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained using a comparator that FDA has determined is appropriate. Detailed documentation must include the clinical study protocol (including a predefined statistical analysis plan), study report, testing results, and results of all statistical analyses.
(ii) Risk analysis and documentation demonstrating how risk control measures are implemented to address device system hazards, such as Failure Modes Effects Analysis and/or Hazard Analysis. This documentation must include a detailed description of a protocol (including all procedures and methods) for the continuous monitoring, identification, and handling of genetic mutations and/or novel respiratory pathogen isolates or strains (
*e.g.,* regular review of published literature and periodic in silico analysis of target sequences to detect possible mismatches). All results of this protocol, including any findings, must be documented and must include any additional data analysis that is requested by FDA in response to any performance concerns identified under this section or identified by FDA during routine evaluation. Additionally, if requested by FDA, these evaluations must be submitted to FDA for FDA review within 48 hours of the request. Results that are reasonably interpreted to support the conclusion that novel respiratory pathogen strains or isolates impact the stated expected performance of the device must be sent to FDA immediately.(iii) A detailed description of the identity, phylogenetic relationship, and other recognized characterization of the respiratory pathogen(s) that the device is designed to detect. In addition, detailed documentation describing how to interpret the device results and other measures that might be needed for a laboratory diagnosis of respiratory infection.
(iv) A detailed device description, including device components, ancillary reagents required but not provided, and a detailed explanation of the methodology, including molecular target(s) for each analyte, design of target detection reagents, rationale for target selection, limiting factors of the device (
*e.g.,* saturation level of hybridization and maximum amplification and detection cycle number, etc.), internal and external controls, and computational path from collected raw data to reported result (*e.g.,* how collected raw signals are converted into a reported signal and result), as applicable.(v) A detailed description of device software, including software applications and hardware-based devices that incorporate software. The detailed description must include documentation of verification, validation, and hazard analysis and risk assessment activities, including an assessment of the impact of threats and vulnerabilities on device functionality and end users/patients as part of cybersecurity review.
(vi) For devices intended for the detection and identification of microbial agents for which an FDA recommended reference panel is available, design verification and validation must include the performance results of an analytical study testing the FDA recommended reference panel of characterized samples. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(vii) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens, the design verification and validation must include a detailed description of the identity, phylogenetic relationship, or other recognized characterization of the Influenza A and B viruses that the device is designed to detect, a description of how the device results might be used in a diagnostic algorithm and other measures that might be needed for a laboratory identification of Influenza A or B virus and of specific Influenza A virus subtypes, and a description of the clinical and epidemiological parameters that are relevant to a patient case diagnosis of Influenza A or B and of specific Influenza A virus subtypes. An evaluation of the device compared to a currently appropriate and FDA accepted comparator method. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(5) When applicable, performance results of the analytical study testing the FDA recommended reference panel described in paragraph (b)(4)(vi) of this section must be included in the device's labeling under § 809.10(b) of this chapter.
(6) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens in addition to detection of SARS-CoV-2 and similar microbial agents, the required labeling under § 809.10(b) of this chapter must include the following:
(i) Where applicable, a limiting statement that performance characteristics for Influenza A were established when Influenza A/H3 and A/H1-2009 (or other pertinent Influenza A subtypes) were the predominant Influenza A viruses in circulation.
(ii) Where applicable, a warning statement that reads if infection with a novel Influenza A virus is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions for novel virulent influenza viruses and sent to State or local health departments for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.
(iii) Where the device results interpretation involves combining the outputs of several targets to get the final results, such as a device that both detects Influenza A and differentiates all known Influenza A subtypes that are currently circulating, the device's labeling must include a clear interpretation instruction for all valid and invalid output combinations, and recommendations for any required followup actions or retesting in the case of an unusual or unexpected device result.
(iv) A limiting statement that if a specimen yields a positive result for Influenza A, but produces negative test results for all specific influenza A subtypes intended to be differentiated (
*i.e.,* H1-2009 and H3), this result requires notification of appropriate local, State, or Federal public health authorities to determine necessary measures for verification and to further determine whether the specimen represents a novel strain of Influenza A.(7) If one of the actions listed at section 564(b)(1)(A) through (D) of the Federal Food, Drug, and Cosmetic Act occurs with respect to an influenza viral strain, or if the Secretary of Health and Human Services determines, under section 319(a) of the Public Health Service Act, that a disease or disorder presents a public health emergency, or that a public health emergency otherwise exists, with respect to an influenza viral strain:
(i) Within 30 days from the date that FDA notifies manufacturers that characterized viral samples are available for test evaluation, the manufacturer must have testing performed on the device with those influenza viral samples in accordance with a standardized protocol considered and determined by FDA to be acceptable and appropriate.
(ii) Within 60 days from the date that FDA notifies manufacturers that characterized influenza viral samples are available for test evaluation and continuing until 3 years from that date, the results of the influenza emergency analytical reactivity testing, including the detailed information for the virus tested as described in the certificate of authentication, must be included as part of the device's labeling in a tabular format, either by:
(A) Placing the results directly in the device's labeling required under § 809.10(b) of this chapter that accompanies the device in a separate section of the labeling where analytical reactivity testing data can be found, but separate from the annual analytical reactivity testing results; or
(B) In a section of the device's label or in other labeling that accompanies the device, prominently providing a hyperlink to the manufacturer's public website where the analytical reactivity testing data can be found. The manufacturer's website, as well as the primary part of the manufacturer's website that discusses the device, must provide a prominently placed hyperlink to the website containing this information and must allow unrestricted viewing access.

## Predicate Devices

- Panther Fusion SARS-CoV-2/Flu A/B/RSV assay ([K222736](/device/K222736.md))

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
> Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/).

{0}

FDA U.S. FOOD & DRUG ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY AND INSTRUMENT

## I Background Information:

A 510(k) Number
K241240

B Applicant
Hologic, Inc.

C Proprietary and Established Names
Panther Fusion SARS-CoV-2/Flu A/B/RSV assay

D Regulatory Information

|  Product Code(s) | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  QOF | Class II | 21 CFR 866.3981 - Device To Detect And Identify Nucleic Acid Targets In Respiratory Specimens From Microbial Agents That Cause The SARS-Cov-2 Respiratory Infection And Other Microbial Agents When In A Multi-Target Test | MI - Microbiology  |

## II Submission/Device Overview:

### A Purpose for Submission:
To expand the Intended Use of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay, which was FDA-cleared under K222736, to include testing of anterior nasal swab (ANS) specimens that have been eluted into UTM/VTM. Additionally, to introduce an Adaptive Crosstalk Correction (ACC) factor in the Assay Definition Module (ADM) software to eliminate potential under correction of crosstalk between the SARS-CoV-2 channel (ROX) and the Flu B channel (RED674) that in some cases produced false Flu B positive results for samples that were SARS-CoV-2 positive, at high titers.

### B Measurand:
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay detects SARS-CoV-2, influenza A, influenza B, and respiratory syncytial virus RNA isolated from nasopharyngeal swab (NPS) specimens and anterior nasal swab (ANS) specimens from individuals with signs and symptoms of a respiratory tract infection.

Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov

{1}

C Type of Test:
This assay is a multiplexed nucleic acid test that detects and differentiates SARS-CoV-2, influenza A, influenza B, and RSV through nucleic acid extraction, amplification, and detection using real-time RT-PCR. All steps of the assay are automated, after the manual addition of sample into the sample lysis tube (SLT) and performed within the Panther and Panther Fusion system.

III Intended Use/Indications for Use:

A Intended Use(s):
See Indications for Use below.

B Indication(s) for Use:
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) swab specimens and anterior nasal (AN) swab specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections.

Nucleic acids from the viral organisms identified by this test are generally detectable in NP and AN swab specimens during the acute phase of infection. The detection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infection are indicative of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.

Positive results do not rule out coinfection with other organisms. The organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system.

The Hologic RespDirect Collection Kit is cleared for NP swab specimens only for testing with the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay.

C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only
For in vitro diagnostic use only

D Special Instrument Requirements:
For use with the Panther Fusion System, only

IV Device/System Characteristics:

A Device Description:
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a multiplex real-time reverse transcriptase PCR (RT-PCR) in vitro diagnostic test developed for use on the fully automated Panther Fusion system to detect and differentiate SARS-CoV-2, influenza A, influenza B, and

K241240 - Page 2 of 17

{2}

respiratory syncytial virus (RSV) directly from nasopharyngeal or anterior nasal swab specimens.

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay cartridge contains the same sample preparation and PCR reaction chemistry as the previously cleared Panther Fusion Flu A/B/RSV assay (K171963). To accommodate addition of the SARS-CoV-2 reagents (primers/probes) to the multiplexed reagents, minor changes were made to the previously cleared analyte primer/probe concentrations and RFU cutoffs. Additionally, the fluorophore for Flu B was changed from ROX to RED647 to accommodate the addition of SARS-CoV-2 to the assay.

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay involves the following steps:

a. Sample lysis - Prior to processing and testing on the Panther Fusion system, specimens are transferred to a Specimen Lysis Tube (SLT) containing specimen transport media (STM). Alternatively, samples can be collected with the RespDirect Collection kit which contains enhanced specimen transport media (eSTM). STM and eSTM lyse the cells, release target nucleic acid and protect them from degradation during storage.

b. Nucleic acid capture and elution - These steps take place in a single tube on the Panther Fusion system. The eluate is transferred to the Panther Fusion system reaction tube containing the assay reagents. The Internal Control-S (IC-S) is added to each test specimen and controls via the working Panther Fusion Capture Reagent-S (wFCR-S). The IC-S in the reagent is used to monitor specimen processing, amplification, and detection. Magnetic particles with covalently bound oligonucleotides mediate the nucleic acid capture. Capture oligonucleotides hybridize to total nucleic acid in the test specimen. Hybridized nucleic acid is then separated from the lysed specimen in a magnetic field. Wash and aspiration steps remove extraneous components debris from the reaction tube. The elution step elutes purified nucleic acid.

c. Elution transfer and multiplex RT-PCR - Eluted nucleic acid is transferred to a Panther Fusion reaction tube already containing oil and reconstituted master mix. A reverse transcriptase generates a DNA copy of the target sequence. Target specific forward and reverse primers and probes then amplify targets while simultaneously detecting and discriminating multiple target types via multiplex RT-PCR. The Panther Fusion system compares the fluorescence signal to a predetermined cut-off to produce a qualitative result for the presence or absence of the analyte. The positive result for each analyte will be accompanied by the cycle threshold (Ct value).

## Hologic RespDirect Collection Kit

An ancillary collection kit that consists of the RespDirect Swab, intended for collection of NP swab specimens, and the enhanced Direct Load Tube (eDLT), containing enhanced specimen transport media (eSTM). This transport media lyses cells, releasing target nucleic acids and protecting them from degradation during storage.

## B Principle of Operation:

The assay detects viral nucleic acids that have been extracted from a patient respiratory sample (i.e., NPS or ANS swab). A multiplex Real-time RT-PCR reaction is carried out under optimized conditions generating amplicons for SARS-CoV-2, influenza A, influenza B, and RSV. The Internal Control-S (IC-S) is added to each test specimen before processing to act as a control for specimen processing, amplification, and detection. Identification of SARS-CoV-2, influenza A, influenza B, RSV, and the IC-S occurs using target-specific primers and fluorescent-labeled probes that hybridize to conserved regions in the viral genomes (Table 1).

K241240 - Page 3 of 17

{3}

Table 1. Assay Primer and Probe Targets

|  Analyte | Gene Targeted | Instrument Channel  |
| --- | --- | --- |
|  SARS-CoV-2 | ORF1ab | ROX  |
|  Influenza A Virus | Matrix | FAM  |
|  Respiratory Syncytial Virus A/B | Matrix | HEX  |
|  Influenza B Virus | Matrix | RED647  |
|  Internal Control-S | Not applicable* | RED677  |

*Internal Control-S is a non-infectious synthetic nucleic acid sequence that is extracted and detected through targeted primers and probes.

C Instrument Description Information:

1. Instrument Name:
Panther System and Panther Fusion System, software version 7.2.7 or 7.2.9.

2. Specimen Identification:
Specimen identification is entered via barcode.

3. Specimen Sampling and Handling:
NPS and ANS specimens collected in transport media.

4. Calibration:
Real Time Fluorometers (RTF) undergo a single calibration during manufacturing. No additional calibration is performed by the end user.

5. Quality Control:
The assay contains an internal control (IC-S) which is added to each test specimen via the working Panther Fusion Capture Reagent-S (wFCR-S). The IC-S is used to monitor specimen processing, amplification, and detection.

Two external controls are also included with this assay in a single use vial, the Panther Fusion SARS-CoV-2/Flu A/B/RSV Positive Control and the Panther Fusion Negative Control. The controls were validated in the analytical and clinical studies.

V Substantial Equivalence Information:

A Predicate Device Name(s):
Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay

B Predicate 510(k) Number(s):
K222736

C Comparison with Predicate(s):

|  Device & Predicate Device(s): | K241240 (Subject) | K222736 (Predicate)  |
| --- | --- | --- |
|  Device Trade Name | Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay | Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay  |

K241240 - Page 4 of 17

{4}

K241240 - Page 5 of 17
|  Device & Predicate Device(s): | K241240 (Subject) | K222736 (Predicate)  |
| --- | --- | --- |
|  **General Device Characteristic Similarities**  |   |   |
|  Regulation Number/Name | Same | 21 CFR 866.3981 – Device To Detect And Identify Nucleic Acid Targets in Respiratory Specimens From Microbial Agents That Cause The SARS-Cov-2 Respiratory Infection And Other Microbial Agents When In A Multi-Target Test  |
|  Product Code(s) | Same | QOF, OOI  |
|  Prescription Use Only | Same | Yes  |
|  Platform | Same | Automated nucleic acid amplification platform.
Uses Panther Fusion system for all steps including nucleic acid extraction, amplification, detection, and result processing  |
|  Technology/Principle of Operation | Same | Multiplexed polymerase chain reaction test  |
|  Assay Controls | Same | Internal and external controls  |
|  Time to Obtain Test Results | Same | ~ 2.5 hours  |
|  Patient Population | Same | Individuals with signs and symptoms of respiratory tract infection  |
|  Intended User | Same | Professional user  |
|  Organisms Detected | Same | SARS-CoV-2, Flu A, Flu B, RSV (RSV A and RSV B)  |
|  **General Device Characteristic Differences**  |   |   |
|  Intended Use | The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) swab specimens and anterior nasal (AN) swab specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the | The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the  |

{5}

K241240 - Page 6 of 17
|  Device & Predicate Device(s): | K241240 (Subject) | K222736 (Predicate)  |
| --- | --- | --- |
|   | to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections.

Nucleic acids from the viral organisms identified by this test are generally detectable in NP and AN swab specimens during the acute phase of infection. The detection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infection are indicative of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.

Positive results do not rule out coinfection with other organisms. The organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system.

The Hologic RespDirect Collection Kit is cleared for NP swab specimens only for testing with the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay. | differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections.

Nucleic acids from the viral organisms identified by this test are generally detectable in NP specimens during the acute phase of infection. The detection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infection are indicative of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.

Positive results do not rule out coinfection with other organisms. The organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system.

The Hologic RespDirect Collection Kit can be used to collect NP specimens for testing with the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay. Additionally, other NP swabs (not provided with the Hologic RespDirect Collection Kit) may be used to collect NP specimens in 3mL of VTM or UTM.

**Ancillary Collection Kit:**
Hologic RespDirect Collection Kit  |

{6}

|  Device & Predicate Device(s): | K241240 (Subject) | K222736 (Predicate)  |
| --- | --- | --- |
|   |  | The Hologic RespDirect Collection Kit is intended to be used for the collection of nasopharyngeal (NP) swab specimens (collected by a healthcare provider) for testing with the Panther Fusion SARS-CoV-2/ Flu A/B/RSV assay.  |
|  Specimen Type/Transport Media Claims | • NPS in VTM/UTM or ANS in VTM/UTM
• NPS in eSTM (RespDirect) | • NPS in VTM/UTM
• NPS in eSTM (RespDirect)  |
|  Adaptive Crosstalk Correction Implemented | Yes | No  |

## VI Standards/Guidance Documents Referenced:

### Standards
- CLSI EP12-A2. User Protocol for Evaluation of Qualitative Test Performance; Approved Guideline – Second Edition.
- CLSI EP17-A2. Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline – Second Edition.
- CLSI EP25. Evaluation of Stability of In Vitro Medical Laboratory Test Reagents; Second Edition.
- CLSI EP37. Supplemental Tables for Interference Testing in Clinical Chemistry; First Edition.
- CLSI EP05-A3. Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline – Third Edition.
- CLSI MM13. Collection, Transport, Preparation, and Storage of Specimens for Molecular Methods; Second Edition.
- CLSI EP07. Interference Testing in Clinical Chemistry; Third Edition.
- CLSI EP15-A3. User Verification of Precision and Estimation of Bias; Approved Guideline – Third Edition.
- CLSI EP24-A2. Assessment of the Diagnostic Accuracy of Laboratory Testing Using Receiver Operating Characteristic Curves; Approved Guideline – Second Edition.
- CLSI EP25-A. Evaluation of Stability of In Vitro Diagnostic Reagents; Approved Guideline.

### Special Controls
Class II Special Controls as per 21 CFR 866.3981

### FDA Guidance Documents
- Respiratory Viral Panel Multiplex Nucleic Acid Assay – Class II Special Controls Guidance for Industry and FDA Staff, October 9, 2009.
- Guidance for Industry and Food and Drug Administration Staff: The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)], July 28, 2014.
- Guidance for Industry and FDA Staff: Content of Premarket Submissions for Device Software Functions, June 14, 2023.

K241240 - Page 7 of 17

{7}

- Guidance for Industry and Food and Drug Administration Staff: Electronic Submission Template for Medical Device 510(k) Submissions, October 2, 2023.
- Guidance for Industry and FDA Staff: Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions, September 27, 2023.

## VII Performance Characteristics (if/when applicable):

### A Analytical Performance:

Since the initial clearance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay (K222736), an Adaptive Crosstalk Correction (ACC) factor was implemented in the Assay Definition Module (ADM) software to eliminate potential under correction of crosstalk between the SARS-CoV-2 (ROX channel) and the Flu B channel (RED674) that in some cases produced false Flu B positive results for samples that were also SARS-CoV-2 high positives. The ACC was evaluated by (1) reanalyzing all analytical and clinical study data collected in support of K222736 with the ACC, except for the Cutoff Study¹, and (2) Performing additional analytical and clinical studies with the ACC to demonstrate that the software changes are effective in eliminating the infrequent occurrence of false Flu B results in the presence of SARS-CoV-2 positive samples.

For those studies originally performed in K222736 and reanalyzed with the new ACC, there were no changes to the study conclusions using the original acceptance criteria. The results of additional analytical studies and clinical studies to support the ACC are presented below. Since there were no other modifications to the assay (e.g., test reagent formulation, etc.), it was unnecessary to repeat several of the studies performed in support of K222736. If a study was not repeated, a reference to where the results can be found (i.e., publicly available K222736 Decision Summary) has been made.

¹Data produced in the Cutoff Study were generated with single target panels/samples which are not affected by Adaptive Crosstalk Correction since cross talk only impacts results where SARS-CoV-2 and Flu B are present. Since the Cutoff Study data did not contain that condition, re-analysis was not performed.

1.  Precision/Reproducibility:
a.  Within-Laboratory Precision
Please refer to the Within-Laboratory Precision Study data presented in the K222736 Decision Summary.
b.  Reproducibility
Please refer to the Reproducibility Study data presented in the K222736 Decision Summary.

2.  Linearity:
Not applicable; this is a qualitative assay.

3.  Analytical Specificity/Interference:
Analytical Reactivity (Inclusivity)
a.  Wet-Testing
Please refer to the Inclusivity Wet-Testing Study data presented in the K222736 Decision Summary.

K241240 - Page 8 of 17

{8}

b. In silico

Please refer to the Inclusivity in silico Study data presented in the K222736 Decision Summary.

Exclusivity Testing

Please refer to the Exclusivity Study data presented in the K222736 Decision Summary.

Cross-Reactivity/Microbial Interference

a. Wet-Testing

Please refer to the Cross-Reactivity/Microbial Interference Wet-Testing Study data presented in the K222736 Decision Summary.

b. In silico

Please refer to the Cross-Reactivity in silico Study data presented in the K222736 Decision Summary.

Interfering Substances

Please refer to the Interfering Substance Study data presented in the K222736 Decision Summary.

Competitive Interference Study Performed with the Adaptive Crosstalk Correction

The purpose of this study was to demonstrate that the Adaptive Crosstalk Correction does not cause competitive interference in co-infected samples containing high levels of SARS-CoV-2 and low levels of Flu B. One SARS-CoV-2 strain (USA-WA1/2020, BEI NR-52281) and one Flu B strain (Victoria lineage, Washington/02/19, Zeptometrix PN:0810611CF) were included in the evaluation. Co-infection panels were made by spiking SARS-CoV-2 at a high concentration (10,000 TCID $_{50}$ /mL) and Flu B at a low concentration (~3x LoD) in pooled negative NP swab VTM/UTM clinical matrix. Three replicates were tested with the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay utilizing the ACC ADM. The results of the competitive interference study are shown in Table 2. No competitive interference was observed at the concentrations tested.

Table 2. Result Summary for Competitive Interference Study

|  Target 1 (Low Conc.) |   | Target 2 (High Conc.) |   | % Detected (# Pos/# Tested)  |   |
| --- | --- | --- | --- | --- | --- |
|  Virus | Conc. | Virus | Conc. | SARS-CoV-2 | Flu B  |
|  Flu B | 0.09 TCID50/mL (3x LoD) | SARS-CoV-2 | 10,000 TCID50/mL (>300,000x LoD) | 100% (3/3) | 100% (3/3)  |

For organism combinations not re-tested in this 510(k), please refer to the Competitive Interference Study data presented in the K222736 Decision Summary.

4. Assay Reportable Range:

Not applicable; this is a qualitative assay.

5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):

a. Controls

K241240 - Page 9 of 17

{9}

The assay contains an internal control (IC-S) added to each test specimen and external positive and negative controls. For more information, see Section IV.C.5. Quality Control, above.

b. Sample Stability
Please refer to the Sample Stability Study data presented in the K222736 Decision Summary.

c. Kit Stability
Please refer to the Kit Stability Study data presented in the K222736 Decision Summary.

d. Shipping Stability
Please refer to the Shipping Stability Study data presented in the K222736 Decision Summary.

6. Detection Limit:

Confirmation of the Flu B Limit of Detection (LoD)
This study was performed to demonstrate that the Adaptive Crosstalk Correction does not alter the established Flu B LoD. The LoD for Flu B was confirmed by testing two (2) strains of Flu B, one (1) Yamagata lineage and one (1) Victoria lineage (Table 3). These are the same strains used to establish the Flu B LoD in K222736. Samples were prepared in pooled negative NP swab VTM/UTM clinical matrix at 1x LoD, as established in K222736. Additionally, dilutions half a log above and below the established LoD were tested to confirm the LoD. Twenty-eight replicates were collected for each strain/concentration combination included in the study. The LoDs of both Flu B strains were confirmed to be the same as previously established in K222736 before the ACC was implemented. The LoD results are summarized in Table 3.

Table 3. LoD Results for Flu B Using the Adaptive Crosstalk Correction
|  Flu B Strain | Conc. (TCID_{50}/mL) | N | % Positive (# Pos/#Tested)  |
| --- | --- | --- | --- |
|  Flu B Victoria lineage
(Washington/02/19), Zeptometrix
PN: 0810611CF | 0.01 | 28 | 100% (28/28)  |
|   |  0.003* | 28 | 96% (27/28)  |
|   |  0.001 | 28 | 71% (20/28)  |
|  Flu B Yamagata lineage
(Phuket/3073/13),
Zeptometrix PN:0810515CF | 0.1 | 28 | 100% (28/28)  |
|   |  0.03* | 28 | 100% (28/28)  |
|   |  0.01 | 28 | 93% (26/28)  |

*LoD established in K222736 prior to implementation of the ACC

The co-spiked LoD was also confirmed to be equivalent to the single analyte spiked samples when using the ACC.

The LoD for the other target analytes is unchanged from K222736. The LoD Study data for these analytes is presented in the K222736 Decision Summary.

7. Assay Cut-Off:
Please refer to the Assay Cut-Off Study data presented in the K222736 Decision Summary.

8. Accuracy (Instrument):
Not applicable.

K241240 - Page 10 of 17

{10}

9. Carry-Over:
Please refer to the Carry-Over Study data presented in the K222736 Decision Summary.

B Comparison Studies:

1. Method Comparison with Predicate Device:
Not applicable.

2. Matrix Comparison:
Please refer to the Matrix Comparison Study data presented in the K222736 Decision Summary.

C Clinical Studies:

1. Clinical Sensitivity:

Prospective Study to Expand the Intended Use to Include an ANS Specimen Claim

The clinical performance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay was established in a multi-center study conducted with two patient-matched ANS specimens that were prospectively collected (i.e., all comers between two time points who meet the inclusion criteria) from individuals with signs and symptoms of respiratory tract infections during the 2022-2023 respiratory illness season. ANS specimens from nine geographically diverse clinical sites in the U.S. were enrolled and tested fresh (Category I specimens) with the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay at three U.S. testing sites.

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay was evaluated for SARS-CoV-2 performance by comparing the candidate device testing results to a composite comparator algorithm (CCA) consisting of three highly sensitive U.S. FDA EUA SARS-CoV-2 molecular tests. A final CCA result was assigned when two of the three composite comparator assays were in concordance. The comparator method utilized to establish performance for the Flu A, Flu B, and RSV targets was a U.S. FDA-cleared molecular Flu A/B/RSV assay. All comparator testing was performed in accordance with the respective package inserts at one central laboratory.

A total of 1268 subjects (each providing two ANS specimens) were acquired and enrolled for the prospective clinical study. Of these 1268 subjects, two were withdrawn because they did not meet the study eligibility criteria, leaving 1266 subjects. Of these 1266 subjects, 77 had their ANS specimens excluded because they were received outside the candidate assay sample stability period, did not have a valid SARS-CoV-2 CCA or Flu A/Flu B/RSV comparator result, or had an invalid candidate device result upon retesting per the Instructions for Use. This left 1189 ANS specimens with evaluable results for SARS-CoV-2, Flu A, Flu B, and RSV.

Of the 1268 subjects enrolled in the study, 1230 had their ANS specimens tested with the candidate device. Ten (10) of these specimens were invalid by the candidate device during testing, for an initial invalid rate of 0.8% (10/1230). Upon retesting, the invalid rate decreased to 0.3% (4/1230).

Table 4 provides a summary of demographic information for the 1189 evaluable specimens included in the prospective clinical study.

K241240 - Page 11 of 17

{11}

Table 4. Demographic Data for Prospectively Collected, Evaluable ANS Specimens

|   |   | Overall  |
| --- | --- | --- |
|  Sex | Male | 474 (39.9%)  |
|   |  Female | 715 (60.1%)  |
|  Age | <5 years | 49 (4.1%)  |
|   |  5-21 years | 162 (13.6%)  |
|   |  22-40 years | 419 (35.2%)  |
|   |  41-60 years | 362 (30.4%)  |
|   |  >60 years | 197 (16.6%)  |
|  Total |   | 1189  |

A summary of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay prospective clinical study performance is provided in Table 5.

Positive Percent Agreement (PPA) was calculated as  $100\% \times (\mathrm{TP} / (\mathrm{TP} + \mathrm{FN}))$ . True positive (TP) indicates that both the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay and the comparator method had a positive result for the specific analyte, and false negative (FN) indicates that the Panther Fusion SARS-CoV-2/Flu A/B/RSV was negative while the comparator result was positive. Negative Percent Agreement (NPA) was calculated as  $100\% \times (\mathrm{TN} / (\mathrm{TN} + \mathrm{FP}))$ . True negative (TN) indicates that both the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay and the comparator method had negative results, and false positive (FP) indicates that the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay was positive while the comparator result was negative. Specimens that obtained discordant results underwent additional testing with a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test, when sufficient sample volume remained.

Table 5. Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay Performance with Prospectively Collected ANS Specimens, Tested Fresh

|  Analyte | Positive Percent Agreement |   |   | Negative Percent Agreement  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  TP/(TP+FN) | % | 95% CI | TN/(TN+FP) | % | 95% CI  |
|  SARS-CoV-2 | 146/1541 | 94.8 | 90.1-97.3 | 1023/10352 | 98.8 | 98.0-99.3  |
|  Flu A | 45/493 | 91.8 | 80.8-96.8 | 1135/11404 | 99.6 | 99.0-99.8  |
|  Flu B | 2/35 | 66.7 | 20.8-93.9 | 1183/11866 | 99.7 | 99.3-99.9  |
|  RSV | 17/187 | 94.4 | 74.2-99.0 | 1169/11718 | 99.8 | 99.4-100  |

TP - true positive; FN - false negative; TN - true negative; FP - false positive; NC - Not applicable
1Three (3) of the 8 specimens with a false negative SARS-CoV-2 result were negative for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test and 4 of the 8 specimens were positive for SARS-CoV-2; 1 specimen was not retested due to insufficient volume. When retested by a second U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test, 5 of the 8 specimens were negative and 3 were positive for SARS-CoV-2.
2One (1) of the 12 specimens with a false positive SARS-CoV-2 result were positive for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test and 11 of the 12 specimens were negative for SARS-CoV-2. When retested by a second U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test, 1 of the 12 specimens was positive and 10 were negative for SARS-CoV-2; 1 specimen was not retested due to insufficient volume.
3One (1) specimen with a false negative Flu A result tested negative for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test; the other 3 specimens were positive for Flu A.

K241240 - Page 12 of 17

{12}

Three (3) specimens with a false positive Flu A result tested positive for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test; the other 2 specimens were negative for Flu A.
5The specimen with a false negative Flu B result tested negative for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
6All 3 specimens with a false positive Flu B result tested negative for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
The specimen with a false negative RSV result tested positive for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
Both specimens with a false positive RSV result tested positive for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.

Data from the NPS specimen prospective clinical study, performed in support of K222736, is shown in Table 6 with the ANS specimen prospective clinical data. For details on the prospective clinical study conducted with NPS specimens, please refer to the Decision Summary for K222736.

Table 6. Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay Performance with Prospectively Collected NPS and ANS Specimens

|  Analyte | Positive Percent Agreement |   |   | Negative Percent Agreement  |   |   |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |  TP/(TP+FN) | % | 95% CI | TN/(TN+FP) | % | 95% CI  |
|  SARS-CoV-2 | NPS | 378/3901 | 96.9 | 94.7-98.2 | 1474/14972 | 98.5 | 97.7-99.0  |
|   |  ANS | 146/1543 | 94.8 | 90.1-97.3 | 1023/10354 | 98.8 | 98.0-99.3  |
|   |  Overall (NPS & ANS) | 524/544 | 96.3 | 94.4-97.6 | 2497/2532 | 98.6 | 98.1-99.0  |
|  Flu A | NPS | 121/123 | 98.4 | 94.3-99.6 | 1709/17146 | 99.7 | 99.3-99.9  |
|   |  ANS | 45/495 | 91.8 | 80.8-96.8 | 1135/11407 | 99.6 | 99.0-99.8  |
|   |  Overall (NPS & ANS) | 166/172 | 96.5 | 92.6-98.4 | 2844/2854 | 99.6 | 99.4-99.8  |
|  Flu B | NPS | 0/0 | NC | NC | 1833/18379 | 99.8 | 99.4-99.9  |
|   |  ANS | 2/38 | 66.7 | 20.8-93.9 | 1183/118610 | 99.7 | 99.3-99.9  |
|   |  Overall (NPS & ANS) | 2/3 | 66.7 | 20.8-93.9 | 3016/3023 | 99.8 | 99.5-99.9  |
|  RSV | NPS | 11/13 | 84.6 | 57.8-95.7 | 1824/1824 | 100 | 99.8-100  |
|   |  ANS | 17/1811 | 94.4 | 74.2-99.0 | 1169/117112 | 99.8 | 99.4-100  |
|   |  Overall (NPS & ANS) | 28/31 | 90.3 | 75.1-96.7 | 2993/2995 | 99.9 | 99.8-100  |

TP - true positive; FN - false negative; TN - true negative; FP - false positive; NC - Not calculable
1Five (5) specimens with false negative SARS-CoV-2 results had sufficient sample volume remaining for discordant testing. All five specimens were positive for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
2Eleven (11) specimens with false positive SARS-CoV-2 results had sufficient sample volume remaining for discordant testing. Seven of the specimens were negative for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
3Three (3) of the 8 specimens with a false negative SARS-CoV-2 result were negative for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test and 4 of the 8 specimens were positive for SARS-CoV-2; 1 specimen was not retested due to insufficient volume. When retested by a second U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test, 5 of the 8 specimens were negative and 3 were positive for SARS-CoV-2.
4One (1) of the 12 specimens with a false positive SARS-CoV-2 result were positive for SARS-CoV-2 by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test and 11 of the 12 specimens were negative for SARS-CoV-2. When retested by a second U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV

K241240 - Page 13 of 17

{13}

molecular test, 1 of the 12 specimens was positive and 10 were negative for SARS-CoV-2; 1 specimen was not retested due to insufficient volume.

${}^{5}$  One (1) specimen with a false negative Flu A result tested negative for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test; the other 3 specimens were positive for Flu A.
Two (2) specimens with false positive Flu A results had sufficient sample volume remaining for discordant testing. Both specimens were negative for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
Three (3) specimens with a false positive Flu A result tested positive for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test; the other 2 specimens were negative for Flu A.
The specimen with a false negative Flu B result tested negative for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
One (1) specimen with a false positive Flu B result had sufficient sample volume remaining for discordant testing. This specimen was negative for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
10All 3 specimens with a false positive Flu B result tested negative for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
11The specimen with a false negative RSV result tested positive for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
12Both specimens with a false positive RSV result tested positive for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay reported a total of 3 prospective, evaluable ANS specimens with co-infections (0.3% of all prospective specimens, 3/1189). All co-infections contained two pathogens, with one specimen containing Flu A and RSV, one specimen containing SARS-CoV-2 and Flu A, and one specimen containing SARS-CoV-2 and RSV. For the candidate assay detected Flu A/RSV co-infection, RSV was not detected by the comparator test. For the candidate assay detected SARS-CoV-2/Flu A co-infection, SARS-CoV-2 was not detected by the comparator test (Table 7).

Table 7. Co-Infections Detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay in the Prospectively Collected ANS Specimens

|  Co-Infection Combination | Number of Specimens | Discrepant Co-Infections1  |
| --- | --- | --- |
|  Flu A + RSV | 1 | 1  |
|  SARS-CoV-2 + Flu A | 1 | 1  |
|  SARS-CoV-2 + RSV | 1 | 0  |
|  Total | 3 | 2  |

1A discrepant co-infection was defined as a specimen that contains at least one pathogen detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay which was not detected by the comparator method.

# Retrospective Clinical Study with ANS Specimens

Flu B and RSV were of lower prevalence and were not encountered in sufficiently large numbers during the prospective clinical study to adequately demonstrate assay performance with ANS specimens. To supplement the results of the prospective clinical study, an evaluation of 175 pre-selected, archived retrospective specimens was performed. These specimens were archived ANS in VTM or UTM that were collected between November 2022 and June 2023. Specimens were selected for enrollment in the study based solely on the historic qualitative result. In addition to evaluating Flu B and RSV positive specimens, Flu A positive specimens were included in the study. Of the 175 specimens, 2 were not included in performance calculations because they had invalid comparator results, leaving 173 specimens. The 173 remaining specimens were

K241240 - Page 14 of 17

{14}

distributed uniformly across two clinical testing sites. A summary of the demographic information for the ANS retrospective specimens is provided in Table 8.

Table 8. Demographic Data for Retrospective ANS Specimens

|   |   | Overall  |
| --- | --- | --- |
|  Sex | Male | 79 (45.7%)  |
|   |  Female | 94 (54.3%)  |
|  Age | <5 years | 63 (36.4%)  |
|   |  5-21 years | 60 (34.7%)  |
|   |  22-40 years | 26 (15.0%)  |
|   |  41-60 years | 15 (8.7%)  |
|   |  >60 years | 9 (5.2%)  |
|  Total |   | 173  |

The performance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay was evaluated by comparing testing results against a U.S. FDA-cleared molecular Flu A/B/RSV assay. The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay retrospective performance data, expressed as positive percent and negative percent agreements against the comparator method, are presented in Table 9 below. Specimens that obtained discordant results underwent additional testing with a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.

Table 9. Panther Fusion SARS-CoV-2/ Flu A/B/RSV Assay Clinical Performance in Retrospective ANS Specimens

|  Target | N | TP | FP | TN | FN | PPA% (95% CI) | NPA % (95% CI)  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  Flu A | 173 | 47 | 2 | 123 | 1 | 97.9% (47/48)1 (89.1-99.6%) | 98.4% (123/125)2 (94.4-99.6%)  |
|  Flu B | 173 | 69 | 0 | 102 | 2 | 97.2% (69/71)3 (90.3-99.2%) | 100% (102/102) (96.4-100%)  |
|  RSV | 173 | 49 | 1 | 122 | 1 | 98.0% (49/50)4 (89.5-99.6%) | 99.2% (122/123)5 (95.5-99.9%)  |

N-number tested; TP - true positive; FN - false negative; TN - true negative; FP - false positive
1The specimen with a false negative Flu A result tested positive for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
2One (1) specimen with a false positive Flu A result tested positive for Flu A by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test; the other specimen was negative for Flu A.
3Both specimens with a false negative Flu B result tested positive for Flu B by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
4The specimen with a false negative RSV result tested negative for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.
5The specimen with a false positive RSV result tested negative for RSV by a U.S. FDA EUA SARS-CoV-2/Flu A/B/RSV molecular test.

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay reported a total of 4 retrospective specimens with multiple pathogen detections (2.3% of all retrospective specimens, 4/173). All co-infections contained two pathogens, with three specimens containing Flu A and RSV and one specimen containing SARS-CoV-2 and RSV. The results are shown in Table 10.

K241240 - Page 15 of 17

{15}

Table 10. Co-infections Detected by the Panther Fusion SARS-CoV-2/ Flu A/B/RSV Assay in Retrospective ANS Specimens

|  Co-Infection Combination | Number of Specimens | Discrepant Co-Infections^{1}  |
| --- | --- | --- |
|  Flu A + RSV | 3 | 2  |
|  SARS-CoV-2 + RSV | 1 | 1  |
|  Total | 4 | 3  |

¹A discrepant co-infection was defined as a specimen that contains at least one pathogen detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay which was not detected by the comparator method.

2. Clinical Specificity:
See section “Clinical Sensitivity” above.

3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):

Retrospective Clinical Study Conducted with SARS-CoV-2 Positive Clinical Specimens to Evaluate the Adaptive Crosstalk Correction

To demonstrate that the Adaptive Crosstalk Correction can resolve unexpected Flu B positives in the presence of SARS-CoV-2, ten individual SARS-CoV-2 high positive archived NP swab clinical specimens (in VTM/UTM) were evaluated with the original ADF (K222736) and the modified ADF containing the ACC. Each specimen was tested once with each ADF. The results are summarized in Table 11. All ten specimens produced Flu B positive results when tested with the original ADF (without the ACC). Upon testing with the new ADF containing the ACC, all Flu B positive results were resolved (i.e., all specimens yielded Flu B negative results), demonstrating that the ACC is functioning as intended.

Table 11. Retrospective SARS-CoV-2 Positive Clinical Specimen Study Results

|  Condition | N | % Positive (# Pos/# Tested)  |   |
| --- | --- | --- | --- |
|   |   |  SARS-CoV-2* | Flu B  |
|  No Adaptive Crosstalk Correction (K222736) | 10 | 100% (10/10) | 100% (10/10)  |
|  With Adaptive Crosstalk Correction | 10 | 100% (10/10) | 0% (0/10)  |

*SARS-CoV-2 positive NPS specimens had high titers (i.e., Ct values ranging from 13.5 - 27.2 per the assay without the ACC). These specimens were reflective of those that yielded false Flu B positive results in the field.

D Clinical Cut-Off:
Not applicable.

E Expected Values/Reference Range:

The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay prospective clinical study included a total of 1268 prospectively collected ANS specimens, of which 1189 were evaluable for SARS-CoV-2, Flu A, Flu B, and RSV. The number and percentage of cases positive for SARS-CoV-2, influenza A, influenza B, and RSV, as determined by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay, are presented below, stratified by collection site.

K241240 - Page 16 of 17

{16}

Table 12. Panther Fusion SARS-CoV-2/Flu A/B/RSV Assay -Expected Values by Specimen Collection Site for ANS Specimens

|  Site | SARS-CoV-2 | Flu A | Flu B | RSV  |
| --- | --- | --- | --- | --- |
|  Total | 13.3% (158/1189) | 4.2% (50/1189) | 0.4% (5/1189) | 1.6% (19/1189)  |
|  Site 1 | 2.2% (2/90) | 0% (0/90) | 0% (0/90) | 1.1% (1/90)  |
|  Site 2 | 7.8% (6/77) | 15.6% (12/77) | 1.3% (1/77) | 7.8% (6/77)  |
|  Site 3 | 3.6% (3/84) | 1.2% (1/84) | 1.2% (1/84) | 1.2% (1/84)  |
|  Site 4 | 13.1% (26/198) | 1.0% (2/198) | 0.5% (1/198) | 0% (0/198)  |
|  Site 5 | 15.5% (50/323) | 4.0% (13/323) | 0.3% (1/323) | 2.5% (8/323)  |
|  Site 6 | 11.1% (5/45) | 2.2% (1/45) | 0% (0/45) | 0% (0/45)  |
|  Site 7 | 25.3% (23/91) | 8.8% (8/91) | 0% (0/91) | 1.1% (1/91)  |
|  Site 8 | 9.6% (11/114) | 2.6% (3/114) | 0% (0/114) | 0% (0/114)  |
|  Site 9 | 19.2% (32/167) | 6.0% (10/167) | 0.6% (1/167) | 1.2% (2/167)  |

F Other Supportive Instrument Performance Characteristics Data: Not applicable.

VIII Proposed Labeling: The labeling supports the finding of substantial equivalence for this device.

IX Conclusion: The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

K241240 - Page 17 of 17

---

**Source:** [https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/QOF/K241240](https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/QOF/K241240)

**Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. If you're preparing [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/), [get in touch](https://innolitics.com/contact).

**Cite:** Innolitics at https://innolitics.com