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The LIAISON® Lyme IgM assay uses chemiluminescent immunoassay (CLIA) technology for the qualitative detection of IgM antibodies to Borrelia burgdorferi in human serum and plasma samples (K2-EDTA, Li-heparin). This assay is intended for use on samples from patients with signs and symptoms consistent with or patients suspected of having Lyme disease to assess the presence of antibodies and exposure to Borrelia burgdorferi. In addition, the LIAISON® Lyme IgM assay may be used as a confirmatory test in the modified two-tier test (MTTT) in combination with the DiaSorin LIAISON® Lyme Total Antibody Plus assay.

If used as a first stage test, positive or equivocal results with the LIAISON® Lyme IgM assay should be confirmed through additional testing with a Standard two-tier test (STTT) methodology using an IgM Borrelia burgdorferi Western blot test following current guidelines.

Positive supplemental results are supportive evidence of the presence of antibodies and exposure to Borrelia burgdorferi and may be used along with patient history, symptoms and other laboratory data to support a clinical diagnosis of Lyme disease.

Negative results by the LIAISON® Lyme IgM assay should not be used to exclude Lyme disease.

The test must be performed on the LIAISON® XL Analyzer.

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

The LIAISON® Lyme IgM assay is an indirect chemiluminescence immunoassay (CLIA) for the qualitative detection of IgM antibodies to Borrelia burgdorferi in human serum and plasma samples. 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 an anti-human IgM mouse monoclonal antibody linked to an isoluminol derivative (isoluminol-antibody conjugate). During the first incubation, anti-Borrelia burgdorferi antibodies present in calibrators, samples or controls bind to the solid phase. Unbound material is then removed with a wash cycle. During the second incubation, the antibody conjugate reacts with anti-Borrelia burgdorferi IgM antibodies that have bound to the solid phase. Excess antibody conjugate is then removed with a wash cycle. Subsequently, the starter reagents are added and a flash chemiluminescence reaction is 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 IgM antibodies present in calibrators, samples or controls.

The provided document describes the LIAISON® Lyme IgM assay, which is a chemiluminescent immunoassay (CLIA) for the qualitative detection of IgM antibodies to Borrelia burgdorferi in human serum and plasma samples. The device performance was evaluated through various studies, including a method comparison with a predicate device, an evaluation using Standard Two-Tier Testing (STTT) and Modified Two-Tier Testing (MTTT) methodologies, testing of a characterized Lyme panel from the CDC, precision and reproducibility studies, a cross-reactivity study, and an interfering substances study.

Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria values for agreement percentages (PPA, NPA) or specificity/sensitivity for the method comparison, STTT, or MTTT studies. Instead, it presents the calculated agreement results, implying these are the performance metrics. For precision and reproducibility, specific %CV ranges are not explicitly stated as acceptance criteria, but the calculated %CV values are reported.

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

• Method Comparison and Prospective MTTT Studies:
  • Sample Size: 2621 human serum specimens.
  • Data Provenance: Collected in 14 states across five (5) distinct U.S. geographical regions. This indicates prospective data.
• Characterized Lyme Panel and Retrospective MTTT Study:
  • Sample Size: 280 samples for the characterized Lyme Panel. For the retrospective MTTT, 279 samples were evaluated after one lacked sufficient volume.
  • Data Provenance: Acquired from the CDC. This indicates retrospective (or banked) data.
• Cross-Reactivity Study:
  • Sample Size: 191 specimens.
  • Data Provenance: From various disease states, implying samples from patients with known conditions, likely retrospective or banked.
• Interfering Substances Study:
  • Sample Size: Not explicitly stated, described as "serum specimens containing B. burgdorferi IgM antibodies."
  • Data Provenance: Not specified, likely laboratory-prepared samples.
• Matrix Equivalence Study:
  • Sample Size: 32 matched patient sets.
  • Data Provenance: Not specified, likely laboratory-prepared or procured patient samples, potentially retrospective.

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

The document does not specify the number or qualifications of experts used to establish the ground truth for the test sets.

4. Adjudication Method for the Test Set

The document does not explicitly describe an adjudication method for the test sets. For the STTT and MTTT, Western blot (WB IgM) is used as a confirmatory test, which acts as a gold standard in the two-tier testing methodology, but it's not described as an "adjudication" in the sense of multiple expert readers resolving discrepancies.

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

This document describes an in vitro diagnostic (IVD) device (an immunoassay), not an AI-powered diagnostic imaging or a reader-assisted device. Therefore, a multi-reader multi-case (MRMC) comparative effectiveness study focusing on human reader improvement with or without AI assistance is not applicable and was not performed.

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

Yes, the studies detailed (Method Comparison, STTT, MTTT, Characterized Lyme Panel, Precision, Reproducibility, Cross-Reactivity, Interfering Substances, Matrix Equivalence) represent the standalone performance of the LIAISON® Lyme IgM assay, which operates as an automated chemiluminescent immunoassay on the LIAISON® XL Analyzer without human interpretation of the primary result (the index value is generated by the machine and then converted to qualitative results). Humans perform the test, but the device provides the result.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The type of ground truth used varies:

• Method Comparison: The predicate device, ZEUS ELISA Borrelia burgdorferi IgM Test System, served as a reference for comparison. While not a "ground truth" in terms of pathology, it's a legally marketed device used for establishing substantial equivalence.
• Standard Two-Tier Testing (STTT): IgM Borrelia burgdorferi Western blot (following current guidelines) was used as the second-tier confirmatory test, representing the established serological "gold standard" for Lyme disease diagnosis, especially when combined with a positive first-tier test and clinical context. This is akin to a reference method ground truth.
• Modified Two-Tier Testing (MTTT): For the prospective study, the STTT protocol (LIAISON® Lyme Total Antibody Plus followed by B. burgdorferi IgM Western Blot) was considered the reference to which the MTTT (LIAISON® Lyme Total Antibody Plus followed by LIAISON® Lyme IgM assay) was compared. For the retrospective study using CDC samples, the STTT WB IgM results associated with the characterized panel served as the comparator.
• Characterized Lyme Panel (CDC): The classification of these samples (Acute, Convalescent, Late Lyme disease, Look-alike Diseases, Healthy controls) implies that these samples have a pre-established clinical and/or laboratory diagnosis/classification, representing a form of clinical ground truth.

8. The Sample Size for the Training Set

The document describes studies for substantial equivalence based on performance evaluation. It does not mention a "training set" in the context of machine learning model development. This is an IVD device, not an AI/ML device that requires explicit training data. The "performance data" presented is for evaluation (test sets).

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

As stated above, this is an IVD device and the document does not refer to a "training set" or "training data" in the typical AI/ML context. The various reference methods (predicate device, Western blot, CDC characterized panels) serve as the comparators or benchmarks for establishing the performance characteristics.

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