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LIAISON® Lyme Total Antibody Plus: The LIAISON® Lyme Total Antibody Plus assay uses chemiluminescent immunoassay (CLIA) technology for the qualitative determination of IgG and IgM antibodies to Borrelia burgdorferi in human serum and plasma (K2-EDTA, Li-heparin) samples. This assay is intended for use on samples from patients with signs and symptoms that are consistent with Lyme disease. Positive or equivocal results should be supplemented by testing with a standardized Western blot procedure. Positive supplemental results provide evidence of exposure to B. burgdorferi and can be used to support a clinical diagnosis of Lyme disease. Negative results by LIAISON® Lyme Total Antibody Plus assay should not be used to exclude Lyme disease. The test has to be performed on the LIAISON® XL Analyzer.

The LIAISON® Lyme Total Antibody Plus Control Set: The LIAISON® Lyme Total Antibody Plus Control Set is intended for use as assayed quality control samples to monitor the performance of the LIAISON® Lyme Total Antibody Plus assay. The performance characteristics of LIAISON® Lyme Total Antibody Plus Control Set have not been established for any other assays or instrument platforms different from the LIAISON® XL.

Device Description

The method for qualitative determination of IgG and IgM antibodies to Borrelia burgdorferi is an indirect chemiluminescence immunoassay (CLIA). All assay steps (with the exception of magnetic particle resuspension) and incubations are performed by the Analyzer. The principal components of the test are magnetic particles (solid phase) coated with recombinant Borrelia antigens and a conjugate reagent containing two mouse monoclonal antibodies (anti- human IgG and anti-human IgM) linked to an isoluminol derivative (isoluminol-antibody conjugate). During the first incubation, antigen-specific antibodies present in calibrators, samples or controls bind to the solid phase. During the second incubation, the conjuqates react with Borrelia burgdorferi IgG and IgM antibodies captured by the solid phase. Unbound material is removed with a wash cycle following incubations. Subsequently, the starter reagents are added and a flash chemiluminescence reaction is thus induced. The light signal, and hence the amount of isoluminol-antibody conjugate, is measured by a photomultiplier as relative light units (RLU) and is indicative of the presence of Borrelia burgdorferi antibodies present in calibrators, samples or controls.

AI/ML Overview

The provided text describes the performance data for the DiaSorin LIAISON® Lyme Total Antibody Plus assay. Here's a breakdown of the acceptance criteria and study details based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined "acceptance criteria" in a table format with pass/fail thresholds. Instead, it presents performance data that supports the claim of substantial equivalence to a predicate device. The implied acceptance criteria are that the new device's performance is comparable to or better than the predicate device across various metrics.

However, we can infer some "performance targets" from the "First Tier Percent Agreement with Predicate Device" and "Second Tier Testing" tables.

Performance Metric	Implied Acceptance Criteria (Goal)	Reported Device Performance (LIAISON® Lyme Total Antibody Plus)
First Tier Agreement:
Positive % Agreement (with Predicate)	High agreement with predicate for positive/equivocal results.	56.5% (65/115) with 95% Cl: 47.4% - 65.2%
Negative % Agreement (with Predicate)	Very high agreement with predicate for negative results.	98.7% (1416/1435) with 95% Cl: 97.9% - 99.2%
Second Tier Testing (PPA):
Positive Percent Agreement (with WB)	High agreement with Western Blot for predicate-positive/test-positive cases	97.9% (47/48) with 95% Cl: 89.1%-99.6%
CDC Lyme Reference Sera Agreement:
Stage I Acute Agreement	High agreement with CDC classification.	76.9% (30/39) with 95% CI: 61.7% - 87.4% (Same as Predicate)
Stage II Convalescent Agreement	High agreement with CDC classification.	93.5% (29/31) with 95% CI: 79.3% - 98.2% (Same as Predicate)
Stage III Late Agreement	Very high agreement with CDC classification.	100.0% (20/20) with 95% CI: 83.9% - 100.0% (Same as Predicate)
Look-alike Diseases Agreement	High negative agreement (low false positives).	95.6% (86/90) with 95% CI: 89.1% - 98.3%
Healthy Controls Agreement	Very high negative agreement (low false positives).	98.0% (98/100) with 95% CI: 93.0% - 99.4%
Precision (Total %CV):	Low variability across runs, days, and operators (lower is better).	<15% for most samples (e.g., Neg Control: 11.3%, Pos Control: 10.4%)
Reproducibility (Total %CV):	Consistent results across different sites (lower is better).	<10% for most samples (e.g., Neg Control: 8.2%, Pos Control: 7.2%)
Cross-Reactivity:	Minimal false positives in various disease states.	13 positive/equivocal results out of 238 samples (approx. 5.5%)
Interfering Substances:	Performance not affected by common interferents at specified concentrations.	Performance not affected (details not explicitly quantified beyond "not affected").
Matrix Equivalence:	Equivalent results across different sample types.	Met acceptance criteria (Passing and Bablok regression summary provided).

2. Sample Size Used for the Test Set and Data Provenance

Prospective Study/Method Comparison Agreement:
- Sample Size: 1550 samples.
- Data Provenance: Samples collected from subjects sent to the lab for Lyme disease testing. De-identified and numbered. From five (5) geographical regions of the U.S.
- Retrospective/Prospective: Implied as prospective given the description "samples collected from subjects sent to the lab for Lyme disease testing."
Characterized Lyme Panel (CDC Lyme Reference Sera):
- Sample Size: 280 samples.
- Data Provenance: Acquired from the CDC.
- Retrospective/Prospective: Retrospective, as these are a "characterized" (pre-defined) panel.
Precision Study: 6 serum samples + 1 lot of controls, tested 48 times each.
Reproducibility Study: 6 serum samples + 2 controls, tested 30 times each per site (total of 90 replicates per sample across 3 sites).
Cross-Reactivity Study: 238 specimens from 24 different disease states.
Interfering Substances: Not specified beyond "equivocal B. burgdorferi serum specimens" and listed substances.
Matrix Equivalence Study: 32 matched patient sets (serum, SST serum, K2-EDTA plasma, lithium heparin plasma).

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The document does not mention the use of experts to establish the ground truth for the test set in the traditional sense of human readers interpreting images.

For the Prospective Study/Method Comparison Agreement, the primary "ground truth" or reference was the predicate device (Zeus ELISA Borrelia VlsE1/pepC10 IgG/IgM Test System) and Western Blot testing for positive/equivocal results.
For the Characterized Lyme Panel, the ground truth was the CDC Reference Classification. The qualifications of those who originally established the CDC classifications are not provided in this document.

4. Adjudication Method for the Test Set

Not applicable in the context of this device (an in vitro diagnostic assay). The "adjudication" is based on agreement with a predicate device, Western Blot, or CDC reference classifications.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

An MRMC study is not relevant here as the device is an in vitro diagnostic (IVD) assay for antibody detection, not an AI-assisted diagnostic imaging tool that would involve human reader interpretation. No human readers or AI assistance in interpretation are mentioned.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

This question is also not directly applicable as the device is a laboratory assay. Its "standalone performance" is essentially what is evaluated throughout the document: the assay's ability to detect antibodies and its agreement with established methods and reference panels. There is no "human-in-the-loop" decision-making process for this specific device's output.

7. The Type of Ground Truth Used

Comparative Effectiveness Study:
- The predicate device (Zeus ELISA Borrelia VlsE1/pepC10 IgG/IgM Test System) served as a primary comparative ground truth.
- Western Blot (a confirmatory laboratory test) was used as a secondary ground truth for resolving positive or equivocal results.
Characterized Lyme Panel:
- CDC Reference Classification which likely represents a consensus or established characterization based on clinical, serological, and potentially epidemiological data for those samples.

8. The Sample Size for the Training Set

The document does not mention a "training set" in the context of machine learning. This device is a biochemical assay, not an AI/ML algorithm. Therefore, the concept of a training set as typically understood in AI development is not applicable. The development of the assay would have involved various optimization and development studies, but these are not referred to as a "training set."

9. How the Ground Truth for the Training Set was Established

As the device is an IVD assay and not an AI/ML algorithm, there is no "training set" or establishment of ground truth for such a set in the conventional sense of AI. The assay's development and optimization would have relied on biochemical principles and validation against known samples, but the document does not detail these initial development phases or the ground truth used therein.

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