LIAISON® MUREX HIV Ab/Ag HT; LIAISON®XL; LIAISON® diluteX
Applicant
DiaSorin, Inc., Stillwater, MN
Product Code
MZF · Microbiology
Decision Date
May 29, 2026
Decision
SESE
Regulation
21 CFR 866.3956
Device Class
Class 2
Attributes
Pediatric
Indications for Use
The LIAISON® Murex HIV Ab/Ag HT is an in vitro chemiluminescent immunoassay for the simultaneous qualitative detection of HIV p24 antigen and antibodies to HIV-1 (Groups M and O) and HIV-2 in human serum (without or with gel-SST) or plasma (lithium and sodium heparin, sodium citrate, and potassium EDTA), on the LIAISON® XL Analyzer or LIAISON® XS Analyzer. It is intended to be used as an aid in the diagnosis of HIV-1/HIV-2 infection, including acute or primary HIV-1 infection. The assay may also be used as an aid in the diagnosis of HIV-1 and/or HIV-2 infection in pediatric subjects (2-21 years) and in pregnant women. The assay cannot distinguish between the detection of HIV p24 antigen and HIV-1/HIV-2 antibodies. The LIAISON® Murex HIV Ab/Ag HT assay is not intended for screening donors of blood or blood products, or human cells or tissues or cellular and tissue-based products (HCT/Ps), or organ donors for HIV.
Device Story
LIAISON® Murex HIV Ab/Ag HT is a sandwich chemiluminescence immunoassay detecting HIV antibodies and p24 antigen simultaneously. Input: human serum or plasma samples. Process: two-incubation phase reaction on magnetic particles coated with recombinant HIV antigens and monoclonal antibodies; isoluminol-labeled conjugates induce flash chemiluminescence measured as relative light units (RLU) by photomultiplier. Output: qualitative detection of HIV-1/2/O antibodies or p24 antigen. Used in clinical laboratories on LIAISON® XL or XS analyzers. LIAISON® diluteX accessory automates water/buffer supply to LIAISON® XL, replacing manual tank refilling and buffer preparation. Healthcare providers use results as an aid in HIV diagnosis; output informs clinical decision-making regarding infection status. Benefits include automated, standardized workflow and reduced manual intervention.
Clinical Evidence
Bench testing only. Precision and reproducibility studies (n=6 samples) showed acceptable SD and %CV. Method comparison (n=115 samples) between manual and automated configurations showed 95.6% overall agreement, with Deming regression slope of 0.976 (r²=0.9402) for samples near the cutoff. Carry-over study confirmed no cross-contamination. Stability testing of Wash/System liquid in diluteX confirmed 28-day stability.
Technological Characteristics
Chemiluminescence immunoassay; magnetic particle solid phase; isoluminol-labeled conjugates. LIAISON® diluteX accessory: fluidic system with pressure regulators, pumps, valves, and independent sensors for automated water/buffer dilution (1:9 ratio). Connectivity: standalone fluidic accessory, no electronic integration with LIAISON® XL. Sterilization: N/A (reagent-based).
Indications for Use
Indicated for qualitative detection of HIV p24 antigen and HIV-1/2 antibodies in human serum or plasma. Population includes pediatric subjects (2-21 years), pregnant women, and adults. Used as an aid in diagnosis of HIV-1/2 infection, including acute/primary HIV-1. Not for blood/tissue donor screening.
Regulatory Classification
Identification
Human immunodeficiency virus (HIV) serological diagnostic and supplemental tests are prescription devices for the qualitative detection of HIV antigen(s) and/or detection of antibodies against HIV in human body fluids or tissues. The tests are intended for use as an aid in the diagnosis of infection with HIV and are for professional use only. The test results are intended to be interpreted in conjunction with other relevant clinical and laboratory findings. These tests are not intended to be used for monitoring patient status, or for screening donors of blood or blood products, or human cells, tissues, and cellular and tissue-based products (HCT/Ps).
Special Controls
*Classification.* Class II (special controls). The special controls for this device are:(1) For all HIV serological diagnostic and supplemental tests
(i) The labeling must include:
(A) An intended use that states that the device is not intended for use for screening donors of blood or blood products or HCT/Ps.
(B) A detailed explanation of the principles of operation and procedures used for performing the assay.
(C) A detailed explanation of the interpretation of results and recommended actions to take based on results.
(D) Limitations, which must be updated to reflect current clinical practice and disease presentation and management. The limitations must include, but are not limited to, statements that indicate:
(
*1* ) The matrices with which the device has been cleared, and that use of this test kit with specimen types other than those specifically cleared for this device may result in inaccurate test results.(
*2* ) The test is not intended to be used to monitor individuals who are undergoing treatment for HIV infection.(
*3* ) A specimen with a reactive result should be investigated further following current guidelines.(
*4* ) All test results should be interpreted in conjunction with the individual's clinical presentation, history, and other laboratory results.(
*5* ) A test result that is nonreactive does not exclude the possibility of exposure to or infection with HIV. Nonreactive results in this assay may be due to analyte levels that are below the limit of detection of this assay.(ii) Device verification and validation must include:
(A) Detailed device description, including the device components, ancillary reagents required but not provided, and an explanation of the methodology. Additional information appropriate to the technology must be included, such as the amino acid sequence of antigen(s) and design of capture antibodies.
(B) For devices with assay calibrators, the design of all primary, secondary, and subsequent quantitation standards used for calibration as well as their traceability to a reference material. In addition, analytical testing must be performed following the release of a new lot of the standard material that was used for device clearance, or when there is a transition to a new calibration standard.
(C) Detailed documentation of analytical performance studies conducted as appropriate to the technology, specimen types tested, and intended use of the device, including, but not limited to, limit of blank, limit of detection, cutoff determination, precision, endogenous and exogenous interferences, cross reactivity, carryover, quality control, matrix equivalency, and sample and reagent stability. Samples selected for use in analytical studies or used to prepare samples for use in analytical studies must be from subjects with clinically relevant circulating genotypes in the United States.
(D) Multisite reproducibility study that includes the testing of three independent production lots.
(E) Analytical sensitivity of the test must be the same as or better than that of other cleared or approved tests. Samples tested must include appropriate numbers and types of samples, including real clinical samples near the lower limit of detection. Analytical specificity of the test must be the same as or better than that of other cleared or approved tests. Samples must include appropriate numbers and types of samples from patients with different underlying illnesses or infections and from patients with potential endogenous interfering substances.
(F) Detailed documentation of performance from a multisite clinical study. Performance must be analyzed relative to an FDA-cleared or approved comparator. This study must be conducted using patient samples, with an appropriate number of HIV positive and HIV negative samples in applicable risk categories. Additional subgroups or types must be validated using appropriate numbers and types of samples. The samples may be a combination of fresh and repository samples, sourced from within and outside the United States, as appropriate. The study designs, including number of samples tested, must be sufficient to meet the following criteria:
(
*1* ) Clinical sensitivity of the test must have a lower bound of the 95 percent confidence interval of greater than or equal to 99 percent.(
*2* ) Clinical specificity of the test must have a lower bound of the 95 percent confidence interval of greater than or equal to 99 percent.(G) Strategies for detection of new strains, types, subtypes, genotypes, and genetic mutations as they emerge.
(H) Risk analysis and management strategies, such as Failure Modes Effects Analysis and/or Hazard Analysis and Critical Control Points summaries and their impact on test performance.
(I) Final release criteria to be used for manufactured test lots with appropriate evidence that lots released at the extremes of the specifications will meet the claimed analytical and clinical performance characteristics as well as the stability claims.
(J) All stability protocols, including acceptance criteria.
(K) Appropriate and acceptable procedure(s) for evaluating customer complaints and other device information that determines when to submit a medical device report.
(L) Premarket notification submissions must include the information contained in paragraph (b)(1)(ii)(A) through (K) of this section.
(iii) Manufacturers must submit a log of all complaints. The log must include the following information regarding each complaint if available: The type of event (
*e.g.,* false negative/false nonreactive or false positive/false reactive), lot, date, population, and whether or not the complaint was reported under part 803 of this chapter (Medical Device Reporting). The log must be submitted annually on the anniversary of clearance for 5 years following clearance of a traditional premarket notification.(2) If the test is intended for Point of Care (PoC) use, the following special controls, in addition to those listed in paragraph (b)(1) of this section apply:
(i) The PoC labeling must include a statement that the test is intended for PoC use.
(ii) The PoC labeling must include the following information near the statement of the intended use:
(A) That the test is for distribution to clinical laboratories that have an adequate quality assurance program, including planned systematic activities that provide adequate confidence that requirements for quality will be met and where there is assurance that operators will receive and use the instructional materials.
(B) That the test is for use only by an agent of a clinical laboratory.
(C) Instructions for individuals to receive the “Subject Information Notice” prior to specimen collection and appropriate information when test results are provided.
(iii) PoC labeling must include instructions to follow current guidelines for informing the individual of the test result and its interpretation.
(iv) The instructions in the labeling must state that reactive results are considered preliminary and should be confirmed following current guidelines.
(v) Device verification and validation for PoC use must include:
(A) Detailed documentation of performance from a multisite clinical study conducted at appropriate PoC sites. Performance must be analyzed relative to an FDA cleared or approved comparator. This study must be conducted using patient samples, with appropriate numbers of HIV positive and HIV negative samples in applicable risk categories. Additional subgroup or type claims must be validated using appropriate numbers and types of samples. The samples may be a combination of fresh and repository samples, sourced from within and outside the United States, as appropriate. If the test is intended solely for PoC use, the test must meet only the performance criteria in paragraphs (b)(2)(v)(A)(
*1* ) and (*2* ) of this section and not the criteria in paragraph (b)(1)(ii)(F) of this section:(
*1* ) Clinical sensitivity of the test must have a lower bound of the 95 percent confidence interval of greater than or equal to 98 percent.(
*2* ) Clinical specificity of the test must have a lower bound of the 95 percent confidence interval of greater than or equal to 98 percent.(B) Premarket notification submissions must include the information contained in paragraph (b)(2)(v)(A) of this section.
(3) If the test is intended for supplemental use in addition to use as an aid in initial diagnosis, the following special controls, in addition to those listed in paragraphs (b)(1) and (2) of this section, as appropriate, apply:
(i) The labeling must include a statement that the test is intended for use as an additional test to confirm the presence of HIV antibodies or antigens in specimens found to be repeatedly reactive by a diagnostic screening test.
(ii) Device validation and verification for supplemental use must include a clinical study, including samples that were initially reactive and repeatedly reactive on a diagnostic test but were negative or indeterminate on a different confirmatory test. Premarket notification submissions must include this information.
(4) If the test is intended solely as a supplemental test, the following special controls, in addition to those listed in paragraphs (b)(1) and (2) of this section, except those in paragraphs (b)(1)(ii)(F) and (b)(2)(v)(A) of this section, as appropriate, apply:
(i) The labeling must include a statement that the test is intended for use as an additional test to confirm the presence of HIV antibodies or antigens in specimens found to be repeatedly reactive by a diagnostic screening test.
(ii) The labeling must clearly state that the test is not for use for initial diagnosis or is not intended as a first-line test.
(iii) Device validation and verification must include a clinical study including samples that were initially reactive and repeatedly reactive on a diagnostic test but were negative or indeterminate on a confirmatory test. Premarket notification submissions must include this information.
(5) If the test is intended to differentiate different HIV types, the following special controls, in addition to those listed in paragraphs (b)(1) through (4) of this section, as appropriate, apply:
(i) The labeling must include the statement that the test is intended for the confirmation of initial results from a diagnostic test and differentiation of different HIV types.
(ii) The results interpretation in the labeling must include instructions for the user on how to interpret the results, including un-typeable and co-infection results.
(iii) Device validation and verification must include evaluation of analytical and clinical sensitivity and specificity for each of the HIV types, strains, and subtypes of HIV intended to be differentiated. Premarket notification submissions must include this information.
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Individuals using assistive technology may not be able to fully access the information contained in this file. For assistance, please call 800-835-4709 or 240-402-8010, extension 1. CBER Consumer Affairs Branch or send an e-mail to: ocod@fda.hhs.gov and include 508 Accommodation and the title of the document in the subject line of your e-mail.
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Diasorin
The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL Analyzer with the LIAISON® diluteX
# 510(k) Summary
# Submitted by:
Carly Cook
Specialist II, Regulatory Affairs
DiaSorin Inc.
1951 Northwestern Avenue
P.O. Box 285
Stillwater, MN 55082-0285
Phone: (b) (6)
Fax: (651) 351-5669
Email: carly.cook@diasorin.com
# Date prepared:
# Name of device:
June 3, 2026
Trade Name:
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL
LIAISON® diluteX
Common Name:
Test, HIV Detection
Micro chemistry analyzer for clinical use
Classification Name:
Human immunodeficiency virus (HIV) serological
diagnostic and/or supplemental test: 21 CFR
866.3956, Class II, Microbiology
Analyzer, Chemistry, Micro, For Clinical Use: 21
CFR 862.2170, Class I, Clinical Chemistry
Product Code:
MZF
JJF
# Predicate Device:
LIAISON® Murex HIV Ab/Ag HT (BK241116)
LIAISON® XL (K141116)
# Device Description
# LIAISON® Murex HIV Ab/Ag HT
The assay simultaneously detects but does not differentiate HIV antibodies and HIV p24 antigen. Qualitative determination of specific antibodies to HIV and HIV p24 antigen is a sandwich chemiluminescence immunoassay. HIV-1 recombinant antigen, HIV-1 group O and HIV-2 biotinylated peptides, and biotinylated monoclonal antibodies to HIV p24 antigen are used for coating magnetic particles (solid phase) and are also linked to isoluminol or fluorescein derivatives (isoluminol antigen/peptides/monoclonal conjugates and fluorescein anti-HIV p24 monoclonal conjugates).
The LIAISON® Murex HIV Ab/Ag HT assay consists of two incubation phases. During the first incubation, HIV antibodies present in samples or controls and HIV p24 antigen present in
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
calibrator, samples or controls bind to the solid phase and, for HIV p24 antigen, to anti-HIV p24 monoclonal labelled with fluorescein derivatives. During the second incubation, HIV-1 antigen, HIV-1 group O, HIV-2 peptides, monoclonal anti-HIV p24 antigen and monoclonal anti-fluorescein linked to an isoluminol derivative (isoluminol-antigen conjugate) react with HIV antibodies, HIV p24 antigen and monoclonal anti-HIV p24 antigen labelled with fluorescein derivatives already bound to the solid phase. After each incubation, the unbound material is removed with a wash cycle. Subsequently, the starter reagents are added and a flash chemiluminescence reaction is thus induced. The light signal, and hence the amount of isoluminol antigen/peptide/monoclonal conjugate, is measured by a photomultiplier as relative light units (RLU) and is indicative of HIV-1/2/O antibodies or HIV p24 antigen presence in calibrator, samples or controls.
### **LIAISON® XL Analyzer with the LIAISON® diluteX**
The LIAISON® diluteX is an accessory for the LIAISON® XL analyzer.
The LIAISON® diluteX interfaces with the LIAISON® XL analyzer in order to automatically fill the LIAISON® XL tanks with purified water and properly pre-diluted LIAISON Wash/System Liquid (code 319100). The LIAISON® diluteX enables automatic dilution of the LIAISON® Wash/System Liquid in a range between 1 to 9.5/10.5 from the more concentrated bottled LIAISON® Wash/System liquid. An accurate fluidic system controlled by pressure regulators, pumps, valves and tubes allows the diluted solution to go out of the system and reach the LIAISON® XL analyzer. By the usage of customized caps installed on the LIAISON® XL analyzer, the LIAISON® diluteX is able to automatically refill the diluted solution in the Wash Buffer tank of the LIAISON® XL analyzer. In the same way, the LIAISON® diluteX is able to refill the deionized water tank of LIAISON® XL analyzer.
### **Intended Use/Indications for Use**
The Intended Use/Indications for Use of the device as described in its current labeling (BK241116) has not changed as a result of the modifications.
### **LIAISON® Murex HIV Ab/Ag HT**
The LIAISON® Murex HIV Ab/Ag HT is an *in vitro* chemiluminescent immunoassay for the simultaneous qualitative detection of HIV p24 antigen and antibodies to HIV-1 (Groups M and O) and HIV-2 in human serum (without or with gel-SST) or plasma (lithium and sodium heparin, sodium citrate, and potassium EDTA), on the LIAISON® XL Analyzer or LIAISON® XS Analyzer. It is intended to be used as an aid in the diagnosis of HIV-1/HIV-2 infection, including acute or primary HIV-1 infection. The assay may also be used as an aid in the diagnosis of HIV-1 and/or HIV-2 infection in pediatric subjects (2-21 years) and in pregnant women. The assay cannot distinguish between the detection of HIV p24 antigen and HIV-1/HIV-2 antibodies.
The LIAISON® Murex HIV Ab/Ag HT assay is not intended for screening donors of blood or blood products, or human cells or tissues or cellular and tissue-based products (HCT/Ps), or organ donors for HIV.
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX^{}[] ---
# **LIAISON® XL**
The LIAISON® XL Analyzer is a Diagnostic System that measures chemiluminescence. It is intended strictly for professional *in-vitro* Diagnostic use. It is to be used only with Chemiluminescence Immunoassays authorized by DiaSorin Italia S.p.A. for the LIAISON® XL instrument.
The analyzer can be connected to a third-party Laboratory Automation System (LAS) which has been previously cleared for use with FDA cleared assays.
# **LIAISON® diluteX**
The LIAISON® diluteX is an accessory for the LIAISON® XL analyzer.
It is designed to automatically dilute the LIAISON® Wash/System Liquid with purified water and to distribute both the purified water and the diluted Wash/System Liquid (referred to as 'Wash Buffer') to each connected LIAISON® XL. The LIAISON® diluteX utilizes purified water (referred to as 'sourced water'), which must be supplied to the device. The device automatically dilutes the LIAISON® Wash/System Liquid, stored on the device, with the sourced water and distributes both the diluted Wash/System Liquid and the sourced water to the LIAISON® XL via separate tubes directly into the analyzer’s tanks.
For professional use only.
# **Comparison to Predicate Device**
The proposed change in this Traditional 510(k) is the introduction of an alternative method for supplying purified water and Wash Buffer to the LIAISON® XL (LXL) for use the LIAISON® assays, including LIAISON® Murex HIV Ab/Ag HT assay.
Table 1 describes in detail the similarities and differences between the current and manual process of supplying Common Liquids to the LXL and the new automatic method supported by the LIAISON® diluteX. The LXL in the standard configuration is considered as predicate device, while the LXL connected to the LIAISON® diluteX qualifies as the candidate device.
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
**Table 1: Comparison of current process and new process - differences and similarities with the predicate device**
| Task, step or action | LIAISON® Murex HIV Ab/Ag HT with manual process LIAISON® XL (Predicate device - BK241116) | LIAISON® Murex HIV Ab/Ag HT with the automated process by means of diluteX LIAISON® XL connected to diluteX |
| --- | --- | --- |
| **Purified Water supply** Provision of purified water to the LXL, upon the liquid level reaching a lower threshold in the tank on board the LXL | The LIAISON® XL analyzer (LXL) signals by means of a display on the Graphical User Interface (GUI) the shortage of purified water; The user accesses the lower cabinet and disconnects the purified water tank from the intermediate tank; The user moves the tank to a purified water faucet; The user fills the tank at the purified water faucet; The user returns the tank to cabinet and reconnect it to the LXL; The LXL detects the increased liquid level; The whole process is possible without interruption of the LXL operation, provided the refilling is faster than the exhaustion of the intermediate tank internal to the LXL. Otherwise, The LXL may need more purified water than the residual in the intermediate tank. The LXL SW shall then independently halt the progression of the routine, before any failure in the purified water provision happens. | The diluteX is connected to a purified water source by a dedicate tube; The diluteX, by means of a sensor of its own in the purified water tank of the LXL and completely independent from the LXL, detects the liquid level below a lower threshold; The diluteX then automatically opens a set of valves, allowing the purified water flowing directly from the faucet to the canister by the tube line connected to the LXL tank; The independent sensor in the canister monitors the liquid level until it reaches an upper threshold; At this point, the diluteX switches the valve set and stops the purified water flow; The whole process is possible without interruption of the LXL operation. Errors in feeding are monitored by the independent SW of the diluteX. Once the minimum threshold of water is detected, the LXL Software (SW) shall independently halt the progression of the routine work. The diluteX has no electrical or electronic connection to the XL analyzer and SW of both systems works independent of each other. |
| **Wash Buffer** Detection of the liquid level reaching a lower threshold in the tank on board the LXL | The LXL signals by means of a display on the GUI the shortage of Wash Buffer. | The diluteX, by means of a sensor of its own in the tank completely independent from the LXL, detects the liquid level below a lower threshold. |
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
| Task, step or action | LIAISON® Murex HIV Ab/Ag HT with manual process LIAISON® XL (Predicate device - BK241116) | LIAISON® Murex HIV Ab/Ag HT with the automated process by means of diluteX LIAISON® XL connected to diluteX |
| --- | --- | --- |
| **Wash Buffer** Preparation of the Wash Buffer from the concentrate | The user accesses the lower cabinet and disconnects the Wash Buffer tank from the intermediate tank; The user manually empties the tank of the remnant of Wash Buffer; The user moves the tank to a purified water faucet; The user rinses the tank and fills the tank at the purified water faucet up to the mark (9 L); The user pours the whole content of a 1 L bottle of LIAISON® Wash/System Liquid in the Wash Buffer tank; The user needs to allow a waiting time of 6 hours to homogenize and degas. | The diluteX is connected to a purified water source by a dedicated tube; The user pours in the LIAISON® Wash/System Liquid tank on the diluteX up to 5 bottles, 1 L each, of concentrate solution; The diluteX, by means of a sensor of its own in the tank completely independent from the LXL, detects the liquid level below a lower threshold; The diluteX automatically opens a set of valves directing the purified water to the dilution pump; The diluteX automatically opens a set of valves directing the LIAISON® Wash/System Liquid to the dilution pump; The dilution pumps add both liquids in a predefined fixed mixing ratio (1 part of the LIAISON® Wash/System Liquid and 9 of purified water) to a mixing line and Wash Buffer intermediate tank. Mixing line and intermediate tank are laid out in a way such that full homogenization is immediately achieved, preventing foam development at the same time. Therefore, the 6-hour waiting time is not required. |
| **Wash Buffer** Provision of the Wash Buffer to the LXL | After the 6 hours of waiting time elapsed, the user reconnects the wash buffer-filled tank to the LXL. The LXL detects the increased liquid level. The whole process is possible without interruption of the LXL operation, provided a second prefilled tank is already available when the former is disconnected. Otherwise, during the 6-hour waiting time, the LXL may need more Wash Buffer than the residual in the intermediate tank internal to the LXL. The LXL SW shall then independently halt the progression of the routine, before any failure in the Wash Buffer provision happens. | The diluteX then automatically opens a set of valves, allowing the Wash Buffer to flow directly from the intermediate tank to the canister by the tube line connected to the LXL tank; The independent sensor in the canister monitors the liquid level until it reaches an upper threshold; At this point, the diluteX switches the valve set, stops the dilution pump and stops the Wash Buffer flow; The whole process is possible without interruption of the LXL operation. Errors in the feeding are monitored by the independent SW of the diluteX. Once the minimum threshold level is detected, the LXL SW independently halts the progression of the washing process. |
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
| Task, step or action | LIAISON® Murex HIV Ab/Ag HT with manual process LIAISON® XL (Predicate device - BK241116) | LIAISON® Murex HIV Ab/Ag HT with the automated process by means of diluteX LIAISON® XL connected to diluteX |
| --- | --- | --- |
| Use of the LIAISON® Wash/System Liquid | The LIAISON® Wash/System Liquid is delivered to the user in 1 L plastic bottles. When needed, a single bottle is poured in a Wash Buffer tank already filled with 9 L of purified water. | The LIAISON® Wash/System Liquid is delivered to the user in 1 L plastic bottles. The content of up to five plastic bottles, for an overall volume of 5 L, can be poured in the dedicated storage tank on the diluteX. The Wash/System liquid in the storage tank is stable for 28 days, and a SW driven maintenance task prompts the user to change the Wash/System liquid after 28 days. |
**No modification is introduced in the LIAISON® Murex HIV Ab/Ag HT device or in any other LIAISON® Assay as a part of this change.**
### **Performance Data:**
A: Analytical studies
#### **1. Precision Study:**
A panel of six samples (HIV negative, HIV-1M, HIV-1 O, HIV-2 low positive, HIV-2 high positive, and p24 Ag) were tested.
One lot of LIAISON® Murex HIV Ab/Ag HT was used.
Samples were tested on [B] (4) LIAISON® XL analyzer connected to [B] (4) LIAISON® diluteX over [B] (4) days, with [B] (4) runs per day, and [B] (4) replicates per run, resulting in [B] (4) replicates per sample. The performance results of the precision study are summarized in Table 2.
**Table 2: Analysis of precision study results**
| Sample | Mean S/CO | Within Run (Repeatability) | | Between Run | | Between Day | | Intermediate Precision | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| HIV NEG | 0.739 | 0.03 | 3.69% | 0.02 | 3.36% | 0.04 | 5.36% | 0.05 | 7.32% |
| HIV-P24 | 3.27 | 0.06 | 1.88% | 0.04 | 1.25% | 0.05 | 1.55% | 0.09 | 2.74% |
| HIV2 LP | 1.26 | 0.04 | 3.00% | 0.00 | 0.00% | 0.03 | 2.60% | 0.05 | 3.87% |
| HIV2-HP | 2.27 | 0.06 | 2.65% | 0.03 | 1.50% | 0.05 | 2.12% | 0.08 | 3.71% |
| HIV-1M | 2.16 | 0.06 | 2.76% | 0.04 | 1.80% | 0.10 | 4.78% | 0.13 | 5.81% |
| HIV-1O | 2.10 | 0.04 | 2.13% | 0.03 | 1.65% | 0.03 | 1.53% | 0.07 | 3.10% |
These results support acceptable precision of the LIAISON® Murex HIV Ab/Ag HT assay run on LIAISON® XL analyzer connected to LIAISON® diluteX.
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Diasorin
The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL Analyzer with the LIAISON® diluteX
## 2. Reproducibility Study
This study was performed at (b) (4) site by testing the LIAISON® Murex HIV Ab/Ag HT assay with (b) (4) LIAISON® XL analyzers, each connected to LIAISON® diluteX. (b) (4) kit lot of LIAISON® Murex HIV Ab/Ag HT and LIAISON® Murex HIV Ab/Ag HT Control kit lot was used.
A panel of six samples (HIV negative, HIV-1M, HIV-1 O, HIV-2 low positive, HIV-2 high positive, and p24 Ag) were tested.
Each panel member was tested over (b) (4) days, on (b) (4) analyzers, with (b) (4) run per day and in (b) (4) replicates per run, resulting in a total of (b) (4) replicates per sample. The test results of the reproducibility study are summarized in Table 3.
Table 3: Analysis of Reproducibility Study results
| Sample | Mean (S/CO) | Intra-Run | | Between Day | | Within Instrument | | Between Instrument | | Overall Reproducibility | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| HIV-NEG | 0.616 | 0.0224 | 3.63% | 0.0252 | 4.09% | 0.0337 | 5.47% | 0.0109 | 1.76% | 0.0354 | 5.75% |
| HIV-P24 | 2.22 | 0.0692 | 3.11% | 0.0383 | 1.72% | 0.0790 | 3.55% | 0.0000 | 0.00% | 0.0790 | 3.55% |
| HIV-2LP | 0.979 | 0.0293 | 2.99% | 0.0282 | 2.88% | 0.0407 | 4.15% | 0.0000 | 0.00% | 0.0407 | 4.15% |
| HIV-2HP | 2.70 | 0.0818 | 3.03% | 0.0534 | 1.98% | 0.0977 | 3.62% | 0.0290 | 1.07% | 0.102 | 3.77% |
| HIV-1M | 1.76 | 0.0669 | 3.80% | 0.0843 | 4.79% | 0.108 | 6.11% | 0.0000 | 0.00% | 0.108 | 6.11% |
| HIV-1O | 1.65 | 0.0559 | 3.38% | 0.0367 | 2.22% | 0.0669 | 4.05% | 0.0000 | 0.00% | 0.0669 | 4.05% |
These results support acceptable reproducibility of the LIAISON® Murex HIV Ab/Ag HT assay run on LIAISON® XL analyzer connected to LIAISON® diluteX.
### 3. Method Comparison with Predicate Device:
This study was conducted to compare the performance of the LIAISON® Murex HIV Ab/Ag HT assay run on the LIAISON® XL analyzer connected to LIAISON® diluteX (candidate) and the assay run on LIAISON® XL analyzer in standard configuration (predicate).
A total of 115 serum and plasma samples (HIV negative, HIV-1, HIV-2, HIV-2, and p24 Ag positive) covering the assay range were used.
One lot of LIAISON® Murex HIV Ab/Ag HT was used.
One lot of LIAISON® Murex Control HIV Ab/Ag HT was used.
Overall agreement was 110/115 (95.6) with five samples being classified as discordant. The test results are summarized in Table 4.
Three of five discordant samples were close to the assay cutoff (1.00 S/CO) with concentrations ranging from 0.98 to 1.11 S/CO on the LIAISON® XL in standard configuration and from 0.75 to 1.07 on the LIAISON® XL connected to diluteX. Positive
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Diasorin
The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL Analyzer with the LIAISON® diluteX
percent agreement (PPA) and negative percent agreement (NPA) are presented in Table 5. A summary of discordant results is presented in Table 6.
Table 4: Overall method agreement
| | Without DiluteX | | Total | |
| --- | --- | --- | --- | --- |
| | | Negative | | Positive |
| With DiluteX | Negative | 50 | 4 | 54 |
| | Positive | 1 | 60 | 61 |
| Total | | 51 | 64 | 115 |
Table 5: Positive percent agreement and negative percent agreement estimates
| | Absolute | Point estimate % | Two-sided 95% CI |
| --- | --- | --- | --- |
| PPA | 60/64 | 93.8 | 84.7 - 98.20 |
| NPA | 50/51 | 98 | 89.5 - 99.80 |
Table 6: Summary of discordant test results
| | Without diluteX | | With diluteX | |
| --- | --- | --- | --- | --- |
| Sample ID | S/CO | Results | S/CO | Results |
| HIVHT-03-B05 | 0.981 | Negative | 1.07 | Positive |
| 15621-500K | 1.03 | Positive | 0.989 | Negative |
| 13159-20K | 1.04 | Positive | 0.855 | Negative |
| 15813-144K | 1.10 | Positive | 0.750 | Negative |
| 15765-200K | 1.11 | Positive | 0.993 | Negative |
To demonstrate the equivalence of LIAISON® Murex HIV Ab/Ag HT assay performance when connected to diluteX and in standard configuration, data derived from the method comparison study was further assessed to evaluate regression between the two configurations. For this purpose, Deming Regression analysis was performed with all samples (Figure 1) as well as with samples close to the cutoff, S/CO of 0.5 – 3.50 (Figure 2). When the entire range of the tested samples is included, the slope is 0.83 and the r² is 0.9957. When the samples with S/CO of 0.5 through 3.50 are plotted, the slope is 0.976 and the r² is 0.9402.
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
**Figure 1:** Scatter Plot of the regression analysis from all samples included in the method comparison study with the LIAISON® Murex HIV Ab/Ag HT assay.
**Figure 2:** Scatter Plot of the regression analysis from samples with S/CO of 0.5 – 3.5 included in the method comparison study with the LIAISON® Murex HIV Ab/Ag HT assay.
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{10}
Diasorin
The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL Analyzer with the LIAISON® diluteX
This study demonstrates that the performance of LIAISON® Murex HIV Ab/Ag HT assay is comparable when run on the LIAISON® XL analyzer with or without the LIAISON® diluteX accessory.
# 4. Carry-Over:
A carryover study was split into two stages as follows:
Stage A: To establish a robust mean signal of the negative sample, five aliquots of the negative sample were tested, twice in duplicates, in two separate runs.
Stage B: To determine any possible contamination from one cuvette to the next, single replicates of the negative sample were tested alternating with a single replicate of the high positive sample. This stage was performed in five separate runs.
One sample with high level of analyte (S/CO above 200) and one negative sample were used.
One lot of LIAISON® Murex HIV Ab/Ag HT and one lot of LIAISON® Murex Control HIV Ab/Ag HT were used.
Samples were tested on three LIAISON® XL analyzers connected to LIAISON® diluteX.
The summary of the carryover study results is presented in Table 7 below. All positive samples were positive.
Table 7: Results of Analyte carryover study
| | Analyzer 1 | | Analyzer 2 | | Analyzer 3 | |
| --- | --- | --- | --- | --- | --- | --- |
| | Stage A | Stage B | Stage A | Stage B | Stage A | Stage B |
| #Positive results | 0 | 0 | 0 | 0 | 0 | 0 |
| %Positive results (in negative samples) | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| #Negative results | 40 | 25 | 40 | 25 | 40 | 25 |
| %Negative results | 100% | 100% | 100% | 100% | 100% | 100% |
The percentage of negative results observed was 100% for both stage A and B, and therefore, no carryover was observed. This study demonstrates that there is no observed cross-contamination or analyte carryover when LIAISON® Murex HIV Ab/Ag HT assay is run on the LIAISON® XL analyzer connected to the LIAISON® diluteX accessory.
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Diasorin
The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT
LIAISON® XL Analyzer with the LIAISON® diluteX
# B. Other Supportive Instrument Performance Characteristics Data:
Stability testing of 10X LIAISON® Wash/Sys liquid in the diluteX tank:
The purpose of this study was to evaluate whether the 10X LIAISON® Wash/Sys liquid is stable when stored on the diluteX accessory. Although the composition of the 10X LIAISON® Wash/Sys liquid has not changed from that approved under the original PMA (BP190437), it is feasible that the stability of the liquid may be affected by the following factors:
1. Leaching of chemicals from the storage container of diluteX
2. Exposure to air in void spaces during storage inside diluteX
3. Potential microbiological contamination due to new pipelines connection between diluteX and the XL Analyzers.
Verification of the chemical stability (monitored by measuring the concentration of peroxide and pH) and microbial contamination were monitored every seven days over a period of 35 days. At all tested time points, peroxide concentration, pH and microbial load were within the acceptable range for all three reagent lots of Wash/System liquid (10X).
The 10X Wash/Sys liquid is required to wash the magnetic particles used in LIAISON® immunoassays and this reagent is common across all of the assays run on the LIAISON® XL analyzers including LIAISON® Murex HIV Ab/Ag HT assay. To assess the stability of the Wash/System liquid within the diluteX container, two FDA-approved representative assays were selected for validation testing. The LIAISON® Murex HBc IgM assay was chosen as an antibody-based assay while the LIAISON® Murex HBsAg Qual assay was selected as an antigen-based assay. The testing was performed on days 28 (T1) and 29 (T2). All samples were tested on one LIAISON® XL analyzer in its standard configuration and connected to a LIAISON® dilute accessory. The agreement of test results was estimated in both conditions for each assay.
1. LIAISON® Murex HBc IgM: A total of 104 samples were tested; on day 28 there were no discordant results observed, while on day 29, one discordant test result was observed. The PPA and NPA are summarized in Table 8.
Table 8: Agreement of test results with LIAISON® Murex HBc IgM assay in standard and diluteX-connected configuration
| Type of agreements | Results |
| --- | --- |
| Positive Agreement T1 | 100% |
| Negative Agreement T1 | 100% |
| Positive Agreement T2 | 100% |
| Negative Agreement T2 | 97.9% |
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**Diasorin**^{}[] The Diagnostic Specialist
LIAISON® Murex HIV Ab/Ag HT^{}[] LIAISON® XL Analyzer with the LIAISON® diluteX
2. LIAISON® Murex HBsAg Qual: A total of 103 samples were tested; on day 28, there were three discordant results observed, while on day 29, there were no discordant test results. The positive and negative percent agreements are summarized in Table 9.
**Table 9:** Agreement of test results with LIAISON® Murex HBsAg Qual assay in standard and diluteX-connected configuration
| Type of agreements | Results |
| --- | --- |
| Positive Agreement T1 | 97.9% |
| Negative Agreement T1 | 96.4% |
| Positive Agreement T2 | 100% |
| Negative Agreement T2 | 100% |
Considering that the discordant test results were close to the cutoff, the stability claim for 10X LIAISON® Wash/System liquid inside the diluteX storage tank for 28 days is acceptable.
### Conclusion
The results of the analytical and method comparison studies demonstrate that the LIAISON® Murex HIV Ab/Ag HT assay for use on the LIAISON® XL analyzer connected to LIAISON® diluteX is as safe, as effective, and performs as well as the predicate device.
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