IntelliSep test
Device Facts
| Record ID | K220991 |
|---|---|
| Device Name | IntelliSep test |
| Applicant | Cytovale, Inc. |
| Product Code | QUT · Microbiology |
| Decision Date | Dec 20, 2022 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.3215 |
| Device Class | Class 2 |
Indications for Use
The Cytovale IntelliSep test is a semi-quantitative test that assesses cellular host response via deformability cytometry of leukocyte biophysical properties and is intended for use in conjunction with clinical assessments and laboratory findings to aid in the early detection of sepsis with organ dysfunction manifesting within the first 3 days after testing. It is indicated for use in adult patients with signs and symptoms of infection who present to the Emergency Department. The test is performed on an EDTA anticoagulated whole blood sample. The IntelliSep test generates an IntelliSep Index value that falls within one of three discrete interpretation bands based on the probability of sepsis with organ dysfunction manifesting within the first three days after testing. The IntelliSep test represents the probability of the clinical syndrome of sepsis and is intended to be used alongside other clinical information and clinical judgement. It does not identify the causative agent of infection and should not be used as the sole basis to determine the presence of sepsis. The IntelliSep test is intended for in vitro diagnostic use.
Device Story
IntelliSep test uses microfluidic deformability cytometry to measure biophysical properties of leukocytes in K2 EDTA venous whole blood; performed on Cytovale System (benchtop analyzer). System modules: Sample Preparation (lyses RBCs, washes leukocytes); Cell Imaging (high-speed video of cells in microfluidic junction); Imaging Analysis (static algorithm processes cell events). Output: IntelliSep Index (ISI, 0.1-10.0) categorized into three interpretation bands (1, 2, 3) indicating sepsis likelihood. Used in Emergency Department by trained operators; results integrated with clinical assessment to aid sepsis detection. Does not identify causative pathogens. Benefits: provides rapid, objective assessment of immune activation state to support clinical decision-making for patients with suspected infection.
Clinical Evidence
Prospective, observational, multicenter cohort study (N=572 evaluable subjects) in US Emergency Departments. Subjects (≥18 years) presented with signs/suspicion of infection. Primary endpoint: Sepsis-3 consensus definition (forced adjudication). Results showed clear relationship between ISI and sepsis likelihood. Sepsis predictive values for Bands 1, 2, and 3 were 11.1%, 28.1%, and 49.4% respectively (forced adjudication). Non-overlapping 80% CIs between bands confirmed statistical distinctness. Study included diverse demographics and comorbidities.
Technological Characteristics
Microfluidic deformability cytometry; measures leukocyte biophysical properties. Benchtop analyzer with three modules: Sample Preparation, Cell Imaging, Imaging Analysis. Specimen: K2 EDTA venous whole blood. Connectivity: barcode scanner, touchscreen GUI, external printer. Software: static algorithm for cell identification and shape quantification. Calibration: factory-set, no user calibration required. Quality Control: two-level stabilized whole blood kit.
Indications for Use
Indicated for adult patients (≥18 years) with signs and symptoms of infection presenting to the Emergency Department to aid in the early detection of sepsis with organ dysfunction manifesting within 3 days of testing.
Regulatory Classification
Identification
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis is identified as an in vitro device intended for the detection and qualitative and/or quantitative measurement of one or more non-microbial analytes in human clinical specimens to aid in the assessment of patients with suspected sepsis when used in conjunction with clinical signs and symptoms and other clinical and laboratory findings.
Special Controls
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis must comply with the following special controls:
*Classification.* Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must include the device's detailed Indications for Use statement describing what the device detects and measures, the results provided to the user, whether the measure is qualitative and/or quantitative, the clinical indications for which the test is to be used, and the specific population(s) for which the device use is intended. (2) Premarket notification submissions must include detailed documentation of the device description, including (as applicable), all device components, software, ancillary reagents required but not provided, explanation of the device principle and methodology, and for molecular devices include detailed documentation of the primer/probe sequence, design, and rationale for sequence selection. (3) Premarket notification submissions must include detailed documentation of applicable analytical studies, such as, analytical sensitivity (Limit of Detection, Limit of Blank, and Limit of Quantitation), precision, reproducibility, analytical measuring range, interference, cross-reactivity, and specimen stability. (4) Premarket notification submissions must include detailed documentation of a prospective clinical study or, if appropriate, results from an equivalent sample set. This detailed documentation must include the following information: (i) Results must demonstrate adequate device performance relative to a well-accepted comparator. (ii) Clinical sample results must demonstrate consistency of device output throughout the device measuring range likely to be encountered in the Intended Use population. (iii) Clinical study documentation must include the original study protocol (including predefined statistical analysis plan), study report documenting support for the Indications for Use(s), and results of all statistical analyses. (5) Premarket notification submissions must include evaluation of the level of the non-microbial analyte in asymptomatic patients with demographic characteristics ( *e.g.,* age, racial, ethnic, and gender distribution) similar to the Intended Use population.(6) As part of the risk management activities performed under 21 CFR 820.10(c) design and development, you must document an appropriate end user device training program that will be offered as part of your efforts to mitigate the risk of failure to correctly operate the instrument. (7) A detailed explanation of the interpretation of results and acceptance criteria must be included in the device's 21 CFR 809.10(b)(9) compliant labeling, and a detailed explanation of the interpretation of the limitations of the samples ( *e.g.,* collected on day of diagnosis) must be included in the device's 21 CFR 809.10(b)(10) compliant labeling.
Predicate Devices
- VIDAS B·R·A·H·M·S PCT (K162827)
Related Devices
- K250912 — IntelliSep Test · Cytovale, Inc. · Nov 19, 2025
- K250513 — IntelliSep Test (CV-ICG-048) · Cytovale, Inc. · Mar 21, 2025
- K232095 — SeptiCyte RAPID · Immunexpress, Inc. · Dec 15, 2023
Submission Summary (Full Text)
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FDA U.S. FOOD & DRUG ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY AND INSTRUMENT
## I Background Information:
A 510(k) Number
K220991
B Applicant
Cytovale Inc.
C Proprietary and Established Names
IntelliSep test
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| QUT | Class II | 21 CFR 866.3215 - Device To Detect And Measure Non-Microbial Analyte(S) In Human Clinical Specimens To Aid In Assessment Of Patients With Suspected Sepsis | MI - Microbiology |
## II Submission/Device Overview:
A Purpose for Submission:
To obtain a substantial equivalence determination for the IntelliSep test on the Cytovale System.
B Measurand:
White blood cells in K2 EDTA venous whole blood
C Type of Test:
Semi-quantitative assay that measures deformability cytometry of white blood cells.
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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III Intended Use/Indications for Use:
A Intended Use(s):
See Indications for Use below.
B Indication(s) for Use:
The Cytovale IntelliSep test is a semi-quantitative test that assesses cellular host response via deformability cytometry of leukocyte biophysical properties and is intended for use in conjunction with clinical assessments and laboratory findings to aid in the early detection of sepsis with organ dysfunction manifesting within the first 3 days after testing. It is indicated for use in adult patients with signs and symptoms of infection who present to the Emergency Department. The test is performed on an EDTA anticoagulated whole blood sample.
The IntelliSep test generates an IntelliSep Index value that falls within one of three discrete interpretation bands based on the probability of sepsis with organ dysfunction manifesting within the first three days after testing. The IntelliSep test represents the probability of the clinical syndrome of sepsis and is intended to be used alongside other clinical information and clinical judgement. It does not identify the causative agent of infection and should not be used as the sole basis to determine the presence of sepsis. The IntelliSep test is intended for in vitro diagnostic use.
C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only
D Special Instrument Requirements:
The IntelliSep test is intended for use on the Cytovale System.
IV Device/System Characteristics:
A Device Description:
The Cytovale IntelliSep test is an in vitro clinical test to aid in the early detection of sepsis with organ dysfunction manifesting within the first three days after testing. It assesses the state of immune activation in patients with clinical suspicion of infection who present in the Emergency Department (ED).
B Principle of Operation:
The IntelliSep test is run on the Cytovale System, a laboratory benchtop analyzer comprised of three modules: Sample Preparation Module, Cell Imaging Module, and Imaging Analysis Module. To run a test, the laboratory operator transfers 100 µL of whole blood into a sample preparation tube which is then placed into the Sample Preparation Module. The Sample Preparation Module automatically lyses red blood cells, and washes the purified leukocytes in a diluent, producing a total volume of approximately 1.0 mL of prepared sample. The operator then transfers the prepared sample to the IntelliSep cartridge for analysis on the Cell Imaging Module. A microfluidic deformability cytometry technique is used to measure the biophysical
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properties of thousands of individual white blood cells in rapid succession. Based on measurements made by the Imaging Analysis Module, the test provides a single score, the IntelliSep Index (ISI), ranging from 0.1-10.0, stratified into three discrete interpretation bands (Band 1, Band 2, and Band 3) of sepsis likelihood.
## C Instrument Description Information:
### 1. Instrument Name:
The IntelliSep test is run on the Cytovale System, a laboratory benchtop analyzer. It is comprised of three modules described in detail below:
- **Sample Preparation Module (SPM)**: accepts patient blood sample in the Sample Preparation Tube, and subsequently lyses the red blood cells in the whole blood sample and washes away red blood cell debris to retain purified white blood cells suspended in a Cytovale Diluent. The operator then pipettes the processed sample into the IntelliSep Cartridge once the SPM completes the preparation process.
- **Cell Imaging Module (CIM)**: positions the IntelliSep Cartridge for imaging, applies pneumatic pressure to drive sample flow through the cartridge, and instructs the camera to capture high speed video of flowing cells as they move through the cartridge’s microfluidic junction. The CIM software further functions to control the graphical user interface and touchscreen and control the external printer and accept input from a barcode scanner.
- **Imaging Analysis Module (IAM)**: uses a static algorithm to identify cells in video data and shape quantification algorithms are used to process cell events into biophysical information per cell. Upon calculating the population representation features, the IAM produces a diagnostic score output called the IntelliSep Index.
### 2. Specimen Identification:
The IntelliSep Test on the Cytovale System is validated for use only with K2 EDTA anticoagulated whole blood. The venous whole blood specimen must be analyzed within five hours of blood draw.
### 3. Specimen Sampling and Handling:
The Sample Processing Module of the Cytovale System receives 100 uL of K2 EDTA anticoagulated whole blood in the Sample Preparation Tube and processes the specimen into a white blood cell sample suspended in Cytovale Diluent. The trained operator injects 1.0 mL of the prepared sample into the IntelliSep Cartridge inlet well and inserts the cartridge into the Cell Imaging Module for analysis. Once the analysis is complete, the Cartridge is disposed according to institutional guidelines on biohazardous waste.
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4. Calibration:
All necessary configuration, qualification, and calibration (where applicable) is performed by a Cytovale technician during installation. Further configuration and calibration procedures are not required by the operator.
Cytovale recommends that the System be serviced every three months of use, based on the initial installation date (or based on the previous service date), or every 3500 tests, whichever comes first.
5. Quality Control:
The IntelliSep Test on the Cytovale System has a two-level quality control (i.e., L1 and L2) set called the IntelliSep Quality Control Kit, derived from stabilized whole blood. The kit contains assayed controls with values within the established measuring range. This test-specific Quality Control Kit should be treated the same way as patient specimens during processing. The mean and range of assay values for a particular lot of the IntelliSep Quality Control Kit (L1 and L2) are reported on the IntelliSep Quality Control Assay Sheet. An Assay Sheet is provided with each lot of materials. They are lot specific and are derived from replicate analyses on Cytovale Systems.
External controls should be tested in accordance with laboratory practices and accreditation requirements per 42 CFR 493.1256.
V Substantial Equivalence Information:
A Predicate Device Name(s): VIDAS BRAHMS PCT
B Predicate 510(k) Number(s): K162827
C Comparison with Predicate(s):
| Device & Predicate Device(s): | K220991 | K162827 |
| --- | --- | --- |
| Device Trade Name | IntelliSep Test | VIDAS B·R·A·H·M·S PCT |
| General Device Characteristic Similarities | | |
| Intended Use/Indications For Use | The Cytovale IntelliSep test is a semi-quantitative test that assesses cellular host response via deformability cytometry of leukocyte biophysical properties | VIDAS B·R·A·H·M·S PCT is an automated test for use on the instruments of the VIDAS family for the determination of human procalcitonin in human serum or plasma |
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| | and is intended for use in conjunction with clinical assessments and laboratory findings to aid in the early detection of sepsis with organ dysfunction manifesting within the first 3 days after testing. It is indicated for use in adult patients with signs and symptoms of infection who present to the Emergency Department. The test is performed on an EDTA anticoagulated whole blood sample. | (lithium heparinate) using the ELFA (Enzyme-Linked Fluorescent Assay) technique. Used in conjunction with other laboratory findings and clinical assessments, VIDAS B·R·A·H·M·S PCT is intended for use as follows: • to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock, to aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, using a change in PCT level over time, • to aid in decision making on antibiotic therapy for patients with suspected or confirmed lower respiratory tract infections (LRTI) defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) – in an inpatient setting or an emergency department, • to aid in decision |
| --- | --- | --- |
| | The IntelliSep test generates an IntelliSep Index value that falls within one of three discrete interpretation bands based on the probability of sepsis with organ dysfunction manifesting within the first three days after testing. The IntelliSep test represents the probability of the clinical syndrome of sepsis and is intended to be used alongside other clinical information and clinical judgement. It does not identify the causative agent of infection and should not be used as the sole basis to determine the presence of sepsis. The IntelliSep test is intended for in vitro diagnostic use. | |
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| | | making on antibiotic discontinuation for patients with suspected or confirmed sepsis. |
| --- | --- | --- |
| General Device Characteristic Differences | | |
| Assay Principle/Method | Microfluidic deformability cytometry | Quantitative immunofluorescent assay |
| Analyte | Leukocyte biophysical properties | Procalcitonin (PCT) |
| Specimen Type | Human venous whole blood (K2 EDTA) | Human serum, plasma (lithium heparinate) |
| Result Output | The IntelliSep Index (ISI, range 0.1 to 10.0) that falls within one of three discrete interpretation bands (Band 1, Band 2, Band 3) based on likelihood of sepsis within three (3) days of testing | Concentration of circulating PCT, in units of ng/mL |
| Instrument Platform | Cytovale System | Instruments of the VIDAS family: VIDAS, miniVIDAS or VIDAS 3 |
| Assay Controls | IntelliSep Quality Control Kit including two levels of controls derived from stabilized whole blood:
• Level 1 Control
• Level 2 Control | Two levels of antigen concentration. Each vial contains lyophilized recombinant PCT in TRIS NaCl buffer (pH 7.3) and preservatives. |
VI Standards/Guidance Documents Referenced:
- CLSI EP05-A3 7-251: Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline - Third Edition
- CLSI EP07 3rd Edition 7-275: Interference Testing in Clinical Chemistry
- CLSI EP25-A 7-235: Evaluation of Stability of In Vitro Diagnostic Reagents; Approved Guideline.
- CLSI EP28-A3c 7-224: Defining Establishing and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline - Third Edition
VII Performance Characteristics (if/when applicable):
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# A Analytical Performance:
# 1. Precision/Reproducibility:
# Within-Lab Precision with Donor Samples
Two within-lab precision studies were conducted with fresh, prospective donor samples to evaluate the impact of operator, instrument, and run-to-run variability with the IntelliSep test on the Cytovale System. Different sample sets at each site were used in lieu of identical sample sets due to a sample stability concerns.
In within-lab precision study #1, four donor samples were tested in three replicates by two operators on two instruments at each of three sites for a total of 12 tests per donor. Results met pre-specified acceptance criteria if the standard deviation for within-lab precision for each samples was $\leq 1.0$ ISI value. Results are presented for within-lab precision study #1 at each site in Tables 1-3.
Table 1: Within-Lab Precision Study #1 at Site 1
| Within Laboratory Precision, Site 1 | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | N | Mean ISI | Band Result | Repeatability | Between-Operator | Between-Instrument | Within-Lab Precision |
| | | | | SD | SD | SD | SD |
| 005-OLL-006 | 12 | 3.98 | 12 Band 1 | 0.17 | 0.02 | 0.20 | 0.26 |
| 005-OLL-001 | 12 | 4.01 | 10 Band 1, 2 Band 2 | 0.80 | 0.53 | 0.00 | 0.96 |
| 005-OLL-004 | 12 | 4.90 | 8 Band 1, 4 Band 2 | 0.25 | 0.06 | 0.00 | 0.26 |
| 005-OLL-002 | 12 | 7.13 | 12 Band 3 | 0.45 | 0.04 | 0.11 | 0.46 |
Table 2: Within-Lab Precision Study #1 at Site 2
| Within Laboratory Precision, Site 2 | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | N | Mean ISI | Band Result | Repeatability | Between-Operator | Between-Instrument | Within-Lab Precision |
| | | | | SD | SD | SD | SD |
| 006-OLL-002 | 12 | 3.24 | 12 Band 1 | 0.41 | 0.00 | 0.40 | 0.57 |
| 005-OLL-032 | 12 | 4.88 | 7 Band 1, 5 Band 2 | 0.42 | 0.34 | 0.22 | 0.58 |
| 005-OLL-034 | 12 | 5.10 | 4 Band 1, 8 Band 2 | 0.29 | 0.00 | 0.31 | 0.42 |
| 005-OLL-033 | 12 | 6.08 | 10 Band 2, 2 Band 3 | 0.31 | 0.00 | 0.00 | 0.31 |
Table 3: Within-Lab Precision Study #1 at Site 3
| Within Laboratory Precision, Site 3 | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | N | Mean ISI | Band Result | Repeatability | Between-Operator | Between-Instrument | Within-Lab Precision |
| | | | | SD | SD | SD | SD |
| 006-UOW-040 | 12 | 2.56 | 12 Band 1 | 0.37 | 0.09 | 0.16 | 0.42 |
| 005-UOW-005 | 12 | 4.68 | 8 Band 1, 4 Band 2 | 0.37 | 0.18 | 0.18 | 0.45 |
| 005-UOW-001 | 12 | 5.53 | 1 Band 1, 11 Band 2 | 0.36 | 0.00 | 0.10 | 0.37 |
| 005-UOW-004 | 12 | 6.41 | 3 Band 2, 9 Band 3 | 0.48 | 0.22 | 0.00 | 0.53 |
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In within-lab precision study #2, precision of samples falling within Band 3 were further evaluated. Four donor samples were evaluated in three replicates by two operators in a single site on two instruments for two separate runs per day for a total of 24 replicates per donor sample. Results are presented for within-lab precision study #2 in Table 4.
Table 4: Within-Lab Precision Study #2
| Sample | N | Mean ISI | Band Result | Repeatability | Between-Run | Between-Operator | Between-Instrument | Within-Lab Precision |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | | | SD | SD | SD | SD | SD |
| 005-OLL-542 | 24 | 24 | 24 Band 3 | 0.29 | 0.07 | 0.00 | 0.00 | 0.30 |
| 005-OLL-684 | 24 | 24 | 24 Band 3 | 0.43 | 0.34 | 0.00 | 0.00 | 0.55 |
| 005-OLL-718 | 24 | 24 | 24 Band 3 | 0.37 | 0.56 | 0.00 | 0.15 | 0.69 |
| 005-OLL-769 | 24 | 24 | 24 Band 3 | 0.39 | 0.21 | 0.14 | 0.07 | 0.47 |
The study design and results from both within-lab precision studies with donor samples are acceptable.
# Reproducibility with Quality Control Materials
A site-to-site reproducibility study was conducted with IntelliSep Quality Control materials (levels 1 and 2) on the Cytovale System across three independent sites. In summary, at each of three sites over 40 days, two Quality Control level materials were tested, with one replicate each for a total of 240 valid test results. Acceptance criteria was a standard deviation of 1.5 ISI values. Results are presented below for each site in Tables 5-8.
Table 5: Within-Lab Precision with QC Material at Site 1
| Site 1 | | | | | |
| --- | --- | --- | --- | --- | --- |
| Sample | Mean | N | Repeatability | Between-Instrument | Total |
| | | | SD | SD | SD |
| QC Level 1 | 1.53 | 40 | 0.71 | 0.58 | 0.92 |
| QC Level 2 | 6.39 | 40 | 0.52 | 0.13 | 0.53 |
Table 6: Within-Lab Precision with QC Material at Site 2
| Site 2 | | | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| Sample | Mean | N | Repeatability | Between-Reagent lot | Between-Instrument | Total |
| | | | SD | SD | SD | SD |
| QC Level 1 | 1.62 | 40 | 0.51 | 0.27 | 0.00 | 0.57 |
| QC Level 2 | 6.25 | 40 | 0.42 | 0.12 | 0.07 | 0.44 |
Table 7: Within-Lab Precision with QC Material at Site 3
| Site 3 | | | | | |
| --- | --- | --- | --- | --- | --- |
| Sample | Mean | N | Repeatability | Between-Reagent lot | Total |
| | | | SD | SD | SD |
| QC Level 1 | 2.25 | 40 | 0.66 | 0.34 | 0.74 |
| QC Level 2 | 6.77 | 40 | 0.46 | 0.36 | 0.58 |
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Table 8: Total Reproducibility with QC Material Among Three Sites
| Site: All | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Sample | Mean | N | Repeatability | Between-Reagent Lot | Total Within-Site | Between-Site | Total |
| | | | SD | SD | SD | SD | SD |
| QC Level 1 | 1.80 | 120 | 0.66 | 0.00 | 0.66 | 0.34 | 0.74 |
| QC Level 2 | 6.47 | 120 | 0.48 | 0.15 | 0.50 | 0.27 | 0.57 |
The results from the reproducibility study with QC materials is acceptable.
2. Linearity:
Not applicable.
3. Analytical Specificity/Interference:
Interference testing was conducted to evaluate the impact of select endogenous and exogenous interferents on the IntelliSep test using the Cytovale System. One Cytovale System, one operator, one lot of the Cytovale Reagent Kit, Cytovale Cleanse, Cytovale Diluent, and IntelliSep Cartridges were used for all testing on a given sample. Three human specimens were evaluated with five interfering substances in the presence and absence of the interferent (or diluent) with four replicates per sample per condition for a total of 120 test results. Acceptance criteria was that the absolute value of the difference between the mean control sample ISI and mean test sample ISI for every interfering substance tested is less than 1.0 unit, at the final concentration tested. Interference study results are presented in Table 9.
Table 9: Interference Study Test Results
| Substance | Concentration | Control Group Mean ISI | Test Group Mean ISI | Mean Difference |
| --- | --- | --- | --- | --- |
| Hemoglobin | 1000 mg/dL | 3.3 | 3.3 | 0.00 |
| Hemolysate | 1000 mg/dL | 2.7 | 2.7 | 0.00 |
| Triglycerides | 1500 mg/dL | 2.5 | 2.7 | -0.20 |
| Conjugated Bilirubin | 40 mg/dL | 2.8 | 3.0 | -0.20 |
| Unconjugated Bilirubin | 40 mg/dL | 3.4 | 3.8 | -0.40 |
Interference study results are acceptable.
4. Assay Reportable Range:
The measuring range of the IntelliSep test is between 0.1 and 10.0 units, divided into three interpretation bands: Band 1 (ISI = 0.1-4.9), Band 2 (ISI = 5.0-6.2), and Band 3 (6.3-10.0).
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
Consumable and Reagent Stability Studies:
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Protocols for real-time stability testing of the IntelliSep Cartridge and Cytovale Reagents (Cytovale Reagent Kit, Cytovale Diluent Reagent, and the Cytovale Cleanse Reagent) were reviewed and found acceptable. These studies are ongoing and will support the use of materials in the IntelliSep test throughout their labeled shelf lives.
## Onboard Reagent Stability
An onboard reagent stability study was conducted with Cytovale Reagents, which consists of the Cytovale Reagent Kit, the Cytovale Cleanse, and the Cytovale Diluent. The study was conducted at one Cytovale site, with one Cytovale System, one operator, one lot of IntelliSep Cartridges, one lot of IntelliSep Quality Control materials, one lot of Cytovale Reagent Kit, one lot of Cytovale Cleanse and one lot of Cytovale Diluent. For each study iteration, three sets of reagents were used, resulting in a total of 12 reagent bottles. All bottles were opened at the first timepoint and stored in simulated onboard conditions of 15°C or 30°C. Onboard reagents were evaluated at 10-, 25-, 30-, 35-, and 45-day timepoints with the IntelliSep Quality Control materials and data were analyzed using a linear regression.
Onboard stability studies with reagent kit, cleanse buffer, and diluent buffer support a 30-day claim at 15-30°C.
## Patient Sample Stability Testing:
A study was conducted to establish the stability of a patient sample over time to produce valid and consistent ISI values. The study was conducted at a single clinical site with 20 patient samples tested hourly for seven consecutive hours. The first timepoint was within 60 minutes from blood draw and subsequent timepoints were flexible within 60-minute time windows up to seven hours. The samples were held at room temperature (18-28°C) between testing time points. For a given sample, one operator completed all runs, using one lot each of Cytovale Reagent Kit, Cytovale Diluent, Cytovale Cleanse, and IntelliSep Cartridges on Cytovale System. An ordinary least squares linear regression was performed using the ISI values for each sample (y-axis) versus time (x-axis). If the slope of the line was not statistically significant from the regression line, then the data were acceptable. If the slope of the line was statistically different from the regression line, then the difference in the claimed test point and final evaluated test point of less than 1.0 ISI values with respect to baseline was considered acceptable.
Study results supported a claim that patient samples are stable for up to 5 hours at room temperature after blood draw with the IntelliSep test on the Cytovale System.
## 6. Detection Limit:
Not applicable.
## 7. Assay Cut-Off:
There are three interpretation bands in the IntelliSep test (Band 1 (ISI = 0.1-4.9), Band 2 (ISI = 5.0-6.2), and Band 3 (6.3-10.0)). Cut-offs were defined ahead of the clinical validation study, and the assay performance was evaluated in the clinical study using those pre-defined cutoffs as compared to adjudicated results.
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8. Accuracy (Instrument):
Not applicable.
9. Carry-Over:
A sample preparation carry-over study was conducted with IntelliSep Quality Controls on the Cytovale System. Testing was conducted over five days with one Cytovale System, one operator, and one lot of IntelliSep Cartridges and reagents. A total of 11 replicates per day were evaluated for the low score QC Level 1 (L1) material and 10 replicates per day were evaluated for the high score QC Level 2 (L2) material. Testing of L1 and L2 followed a fixed sequence of 21 runs each day to allow the following four group analyses: L1 run preceded by a L1 run (LL), L1 run preceded by a L2 run (HL), L2 run preceded by a L1 run (LH), and L2 run preceded by a L2 run (HH). Study results were considered acceptable if HL did not increase beyond 1 ISI value relative to a LL and LH did not decrease beyond 1 ISI value relative to a HH. Results are presented in Table 10 below.
Table 10: Sample Carryover Results
| Days | LL | HL | LL - HL Difference | HH | LH | HH - LH Difference |
| --- | --- | --- | --- | --- | --- | --- |
| Day 1 | 2.46 | 2.22 | 0.24 | 7.28 | 7.40 | -0.12 |
| Day 2 | 2.14 | 2.20 | -0.06 | 7.00 | 7.24 | -0.24 |
| Day 3 | 2.36 | 2.32 | 0.04 | 7.14 | 6.90 | 0.24 |
| Day 4 | 2.34 | 2.42 | -0.08 | 7.18 | 6.90 | 0.28 |
| Day 5 | 1.98 | 2.00 | -0.02 | 7.02 | 7.08 | -0.06 |
| Total | 2.26 | 2.23 | 0.03 | 7.12 | 7.10 | 0.02 |
A low QC sample preceded by a high QC sample does not increase the ISI value by +1 and a high QC samples preceded by a low QC sample does not decrease the ISI value by -1. Therefore, the sample carryover study design and results are acceptable.
B Comparison Studies:
1. Method Comparison with Predicate Device:
Not applicable.
2. Matrix Comparison:
Not applicable.
C Clinical Studies:
1. Clinical Sensitivity:
A blinded, prospective, multi-site clinical study was conducted at four sites comprised of both academic and community hospital emergency departments in the United States. The clinical study was designed to evaluate the performance of the IntelliSep test on the Cytovale
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System for the early detection of sepsis with organ dysfunction manifesting within three days after testing in patients admitted to an Emergency Department. IntelliSep test performance was established using the Sepsis-3 (Singer, JAMA 2016 consensus criteria) definition as the primary endpoint and the Sepsis-2 (ACCP/SCCM 2001 consensus criteria) definition for 'Sepsis' and 'Severe Sepsis' as the secondary endpoints. The clinical endpoints were predefined to demonstrate the association of the IntelliSep Index (expressed in terms of its Interpretation Bands) with the probability of sepsis determined by clinical adjudication as a non-reference method. A successful association is demonstrated by the non-overlap of the predictive value 80% confidence intervals around point estimates for the probability of detecting sepsis with organ dysfunction in Bands 1 and 3.
A total of 599 study subjects were enrolled based on the following inclusion criteria:
- ≥ 18 years old
- The first vital sign (any one of: blood pressure, temperature, pulse, or respiratory rate) has been recorded in the medical record
- A blood sample originally collected in a K2 EDTA tube within 4 hours of the first recorded vital sign
- Sign or suspicion of infection as defined either as 2+ Systemic Inflammatory Response Syndrome (i.e., fast heart rate, low blood pressure, low or high body temperature, and low or high white blood cell count) or orders placed for cultures of suspected bodily fluids
After excluding study participants for meeting exclusion criteria, sample stability issues, or assay issues, a total of 572 evaluable study subjects remained.
Study personnel in every tier of the process were blinded to the IntelliSep test results. Site personnel at each clinical site completed a review of the study subjects' medical records and collected objective evidence of infection and organ dysfunction to meet the Sepsis-3 and Sepsis-2 consensus standard definitions. The objective evaluation served as a normalizing standard across all investigators and sites and provided the starting point for adjudication. Sequential Organ Failure Assessment (SOFA) scores were calculated for up to 3 days following presentation, and organ dysfunction was defined as an increase in SOFA score of 2 or more points over baseline. Approximately 30 days after the subjects were enrolled, Site Investigators completed a clinical impression form of the subject's disease course. Briefly, upon completion of the clinical impression form and following medical monitor approval, a case report summary (CRS) of each participant was sent to two independent physician adjudicators. If the two adjudicators agreed in their determination, the case was considered unanimous adjudication (i.e., adjudicators came to the same conclusion independent of one another). If there was a disagreement between the two adjudicators, the CRS was sent to a third adjudicator and a Clinical Adjudication Committee consensus meeting was held and the case would fall under consensus (i.e., agreement among three adjudicators after discussion) or forced (i.e., disagreement among adjudicators and majority vote is deciding factor) adjudication schemes.
Results of the primary endpoint to determine the association of the IntelliSep Test results with the probability of Sepsis-3 using a forced adjudication scheme are presented in Table 11.
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Table 11: Sepsis-3 definition, forced adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 28 | 224 | 11.1% (8.6%, 14.1%) | 0.35 |
| Band 2 | 45 | 115 | 28.1% (23.5%, 33.2%) | 1.08 |
| Band 3 | 79 | 81 | 49.4% (44.0%, 54.7%) | 2.69 |
| | | | Sepsis Prevalence | |
| Total | 152 | 420 | 26.6% | NA |
The primary endpoint is met since the 80% CIs for Band 1 and Band 3 in sepsis predictive value do not overlap.
Results of the secondary endpoints to determine the association of the IntelliSep test results with the probability of Sepsis-2 (sepsis and severe sepsis) using a forced adjudication scheme are presented in Tables 12-13.
Table 12: Sepsis-2 (sepsis) definition, forced adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 60 | 154 | 28.0% (24.0%, 32.4%) | 0.38 |
| Band 2 | 88 | 60 | 59.5% (53.9%, 64.9%) | 1.44 |
| Band 3 | 113 | 42 | 72.9% (67.8%, 77.6%) | 2.64 |
| | | | Sepsis Prevalence | |
| Total | 261 | 256 | 50.5% | NA |
Table 13: Sepsis-2 (severe sepsis) definition, forced adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 34 | 180 | 15.9% (12.7%, 19.6%) | 0.31 |
| Band 2 | 65 | 83 | 43.9% (38.4%, 49.5%) | 1.28 |
| Band 3 | 97 | 58 | 62.6% (57.2%, 67.7%) | 2.74 |
| | | | Sepsis Prevalence | |
| Total | 196 | 321 | 37.9% | NA |
The secondary endpoints are met since the 80% CIs for Band 1 and Band 3 in sepsis predictive value do not overlap.
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Data to evaluate the study's tertiary endpoints which include the association of the IntelliSep Test results with the probability of sepsis-3 and sepsis-2 (sepsis and severe sepsis) using the unanimous and consensus adjudication schemes are presented in Tables 14-19 below as an additional supplemental analysis.
Table 14: Sepsis-3 definition, consensus adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 28 | 222 | 11.2% (8.7%, 14.2%) | 0.35 |
| Band 2 | 45 | 115 | 28.1% (23.5%, 33.2%) | 1.08 |
| Band 3 | 79 | 81 | 49.4% (44.0%, 54.7%) | 2.68 |
| | | | Sepsis Prevalence | |
| Total | 152 | 418 | 26.7% | NA |
Table 15: Sepsis-3 definition, unanimous adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 20 | 186 | 9.7% (7.1%, 12.9%) | 0.31 |
| Band 2 | 34 | 86 | 28.3% (23.0%, 34.3%) | 1.14 |
| Band 3 | 62 | 62 | 50.0% (43.9%, 56.1%) | 2.88 |
| | | | Sepsis Prevalence | |
| Total | 116 | 334 | 25.8% | NA |
Table 16: Sepsis-2 definition, consensus adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 60 | 153 | 28.2% (24.2%, 32.5%) | 0.38 |
| Band 2 | 88 | 60 | 59.5% (53.9%, 64.9%) | 1.43 |
| Band 3 | 113 | 42 | 72.9% (67.8%, 77.6%) | 2.63 |
| | | | Sepsis Prevalence | |
| Total | 261 | 255 | 50.6% | NA |
Table 17: Sepsis-2 definition, unanimous adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 37 | 143 | 20.6% (16.7%, 24.9%) | 0.34 |
| Band 2 | 58 | 54 | 51.8% (45.3%, 58.2%) | 1.41 |
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Table 18: Sepsis-2 (severe sepsis) definition, consensus adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 34 | 179 | 16.0% (12.8%, 19.7%) | 0.31 |
| Band 2 | 65 | 83 | 43.9% (38.4%, 49.5%) | 1.28 |
| Band 3 | 97 | 58 | 62.6% (57.2%, 67.7%) | 2.73 |
| | | | Sepsis Prevalence | |
| Total | 196 | 320 | 38.0% | NA |
Table 19: Sepsis-2 (severe sepsis) definition, unanimous adjudication scheme
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) | Sepsis Likelihood Ratio |
| --- | --- | --- | --- | --- |
| Band 1 | 20 | 160 | 11.1% (8.2%, 14.7%) | 0.25 |
| Band 2 | 43 | 69 | 38.4% (32.3%, 44.8%) | 1.23 |
| Band 3 | 75 | 44 | 63.0% (56.8%, 68.9%) | 3.37 |
| | | | Sepsis Prevalence | |
| Total | 138 | 273 | 33.6% | NA |
The tertiary endpoints successfully met the pre-established acceptance criteria since the $80\%$ CIs for Band 1 and Band 3 in sepsis predictive value do not overlap.
IntelliSep Test results stratified by Interpretation Band and demographic information for the 572 evaluable study subjects is summarized in Table 20 below.
Table 20: Demographic Information Stratified by IntelliSep Test Interpretation Band Results
| Population Characteristic | IntelliSep Test Results | | | |
| --- | --- | --- | --- | --- |
| | | Band 1 (N = 252) | Band 2 (N = 160) | Band 3 (N = 160) |
| Age | Median (Q1 – Q3) | 54.0 (39.5 - 67.0) | 56.0 (39.0 - 68.0) | 58.0 (41.5 - 71.0) |
| | Subjects ≥ 65, N (%) | 77 (30.56%) | 54 (33.75%) | 56 (35.00%) |
| Sex, N (%) | Female | 106 (42.06%) | 68 (42.50%) | 76 (47.50%) |
| | Male | 146 (57.94%) | 92 (57.50%) | 84 (52.50%) |
| Ethnicity, N (%) | Hispanic | 20 (7.94%) | 8 (5.00%) | 7 (4.38%) |
| | Non-Hispanic | 227 (90.08%) | 148 (92.50%) | 152 (95.00%) |
| | Not Provided | 5 (1.98%) | 4 (2.50%) | 1 (0.62%) |
| Race (%) | American Indian or Alaska Native | 2 (0.79%) | 3 (1.88%) | 3 (1.88%) |
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Additional descriptive non-powered analyses were performed to explore test performance by sex in Table 21 and age in Table 22.
Table 21: Demographic Subgroup Analysis – Results for Sepsis-3 Forced Adjudication by Sex
| Females (n=250) | | | |
| --- | --- | --- | --- |
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) |
| Band 1 | 9 | 97 | 8.5% (5.2%, 13.1%) |
| Band 2 | 19 | 49 | 27.9% (20.8%, 36.1%) |
| Band 3 | 29 | 47 | 38.2% (30.7%, 46.1%) |
| Males (n=322) | | | |
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) |
| Band 1 | 19 | 127 | 13.0% (9.5%, 17.3%) |
| Band 2 | 26 | 66 | 28.3% (22.1%, 35.1%) |
| Band 3 | 50 | 34 | 59.5% (52.0%, 66.7%) |
Table 22: Demographic Subgroup Analysis – Results for Sepsis-3 Forced Adjudication by Age
| Age < 65 (n=385) | | | |
| --- | --- | --- | --- |
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) |
| Band 1 | 17 | 158 | 9.7 (6.9%, 13.2%) |
| Band 2 | 25 | 81 | 23.6% (18.3%, 29.7%) |
| Band 3 | 41 | 63 | 39.4% (33.0%, 46.2%) |
| Age ≥ 65 (n=187) | | | |
| IntelliSep Result | Adjudicated + | Adjudicated - | Sepsis Predictive Value (80% CI) |
| Band 1 | 11 | 66 | 14.3% (9.3%, 20.8%) |
| Band 2 | 20 | 34 | 37.0% (28.2%, 46.6%) |
| Band 3 | 38 | 18 | 67.9% (58.6%, 76.1%) |
The acceptance criteria for the clinical study were met for the IntelliSep test on the Cytovale System to aid in the early detection of sepsis with organ dysfunction manifesting within three days after testing.
2. Clinical Specificity:
See Clinical Sensitivity section for relevant information.
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3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
Not applicable.
## D Clinical Cut-Off:
The Cytovale IntelliSep test cut-off values were established prior to the clinical trial. The following IntelliSep interpretation bands are supported by the results from the prospective observational multi-site clinical trial, the CV-SQuISH-ED trial (Clinicaltrials.gov identifier: NCT04933760), specifically Tables 11-13.
Table 23: IntelliSep Test Band and Result Interpretation Table
| IntelliSep Interpretation Band | ISI Range | Results Interpretation Considerations |
| --- | --- | --- |
| BAND 1
(Low Probability of Sepsis) | 0.1 to 4.9 | All results should be interpreted in the context of the other clinical observations and laboratory test results for the patient. |
| BAND 2 | 5.0 to 6.2 | |
| BAND 3
(High Probability of Sepsis) | 6.3 to 10.0 | |
## E Expected Values/Reference Range:
A reference range study was conducted to establish the IntelliSep test with healthy donors using K2 EDTA anticoagulated venous whole blood samples. Samples were collected from a total of 243 healthy donors consisting of 120 self-reported female donors and 123 self-reported male donors for 243 valid IntelliSep test results. Demographic information of the 243 healthy donors is provided in Tables 24-25.
Table 24: Demographics of Reference Range Healthy Donors
| Gender | Band 1 | Band 2 | Band 3 | Total |
| --- | --- | --- | --- | --- |
| Female | 120 | 0 | 0 | 120 |
| Male | 120 | 2 | 1 | 123 |
| | | | | |
| Race | Band 1 | Band 2 | Band 3 | Total |
| Asian | 10 | 0 | 0 | 10 |
| Black or African American | 21 | 0 | 0 | 21 |
| White | 196 | 2 | 1 | 199 |
| Other | 13 | 0 | 0 | 13 |
| | | | | |
| Ethnicity | Band 1 | Band 2 | Band 3 | Total |
| Hispanic | 11 | 0 | 0 | 11 |
| Non-Hispanic | 229 | 2 | 1 | 232 |
| | | | | |
| Age | Band 1 | Band 2 | Band 3 | Total |
| Under 65 years | 227 | 1 | 1 | 229 |
| 65 years and over | 13 | 1 | 0 | 14 |
The 95% confidence intervals for IntelliSep Index values by sex in Table 25.
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Table 25: Reference Range Bounds and Confidence Intervals with Healthy Donors
| | 95% Reference Range | Lower Reference Limit (90% CI) | Upper Reference Limit (90% CI) |
| --- | --- | --- | --- |
| Combined | 0.9-4.7 | 0.7-1.1 | 4.3-4.9 |
| Female | 0.7-4.7 | 0.4-1.2 | 4.1-4.7 |
| Male | 1.0-4.6 | 0.9-1.2 | 4.2-5.0 |
The Reference Range for the Cytovale IntelliSep test was found to be 0.7-4.7 for females and 1.0-4.6 for males and found to be acceptable.
Laboratories and other users should establish their own reference intervals for their patient populations using the IntelliSep test to reflect potential sources of variability, such as patient gender, race, age, and preparation techniques.
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.
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