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This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of antimitochondrial antibodies in human serum. The presence of mitochondrial antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of primary biliary cirrhosis(PBC)

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of antibodies to mitochondrial antigen in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified mitochondrial antigen has been attached to the inner surfaces of the microwell plate. During the initial incubation step, antibodies in patient serum bind specifically to the immobilized antigen and remain in place after a wash step. A second antibody which is conjugated to horseradish peroxidase (HRP) is used to recognize the "heavy + light" chain regions of the patient's antibodies remaining after the wash step. In the wells where the second antibody remains bound, the conjugated HRP catalyzes a color change in the substrate, tetramethyl benzidine (TMB). After the reaction is stopped, the color is read in an EIA Plate reader.

The provided document describes the VIRGO® AMA ELISA KIT, an enzyme-linked immunosorbent assay designed for the detection and measurement of antimitochondrial antibodies in human serum. This device is intended to aid in the diagnosis of primary biliary cirrhosis (PBC) when used in combination with clinical observations and other serological tests.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria with numerical targets. However, based on the comparative testing and precision studies, the implied criteria are:

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

• Precision Studies:
  • Inter-assay: 12 different samples (9 positive, 3 negative).
  • Intra-assay: The same 12 samples (9 positive, 3 negative).
  • Data Provenance: Not specified, but likely from a laboratory setting. No country of origin is mentioned. The studies are prospective in nature to evaluate device performance.
• Comparative Testing:
  • Total Test Set Size: 154 serum specimens.
  • Breakdown: 68 specimens from individuals with known or suspected liver disease and 86 from normal, apparently healthy donors.
  • Data Provenance: Not specified, but likely from a clinical or laboratory setting. No country of origin is mentioned. These are retrospective samples as they are "known" cases or "normal" donors.

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

The document does not explicitly mention the use of "experts" to establish ground truth in the typical sense of subjective interpretation (e.g., radiologists). Instead, the "ground truth" for the comparative testing is based on:

• Predicate Device Results: The Scimedx Mitochondrial Antibody Test System is used as the comparative standard.
• Clinical Status: 68 samples were from "individuals with known or suspected liver disease," and 86 were from "normal apparently healthy donors." This implies clinical diagnosis or health status was used for initial classification.

Therefore, the ground truth is established by a combination of a legally marketed predicate device's results and, for the clinical samples, presumably by physician diagnosis based on clinical observations and other serological tests. No specific number of experts or their qualifications for establishing human ground truth are provided, as the method relies on objective test results and clinical status.

4. Adjudication Method for the Test Set

No explicit adjudication method (e.g., 2+1, 3+1) is mentioned. The comparison testing directly compares the proposed device's results against the predicate device's results. For the clinical samples, the "known or suspected liver disease" and "normal" classifications serve as the basis, implying that a clinical consensus or established diagnostic criteria were already in place for those classifications. However, no specific adjudication of discrepant results between the proposed device and the predicate device is detailed beyond the direct numerical comparison shown in the tables.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study was not done. This device is an immunoassay (ELISA kit), which produces objective numerical optical density (OD) readings that are then interpreted against a fixed cutoff to determine a positive or negative result. It does not involve human readers interpreting images or data in a subjective manner that would necessitate an MRMC study to evaluate human performance with or without AI assistance.

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

Yes, the performance presented for the VIRGO® AMA ELISA KIT is a standalone performance. The device is a laboratory assay where samples are processed, and the results (optical density readings) are automatically generated and interpreted against a predetermined cutoff value without human interpretation or intervention in the diagnostic decision of the device itself. The results are then reported as positive or negative. The listed "Relative Sensitivity" is a standalone metric.

7. The Type of Ground Truth Used

The ground truth used for performance evaluation is primarily:

• Predicate Device Results: For direct comparison and performance evaluation, the results from the legally marketed Scimedx Mitochondrial Antibody Test System serve as the gold standard or reference.
• Clinical Diagnosis/Outcomes Data: For the 68 "known or suspected liver disease" specimens and 86 "normal apparently healthy donors," the ground truth is based on established clinical diagnoses or health status, which would derive from a combination of patient history, physical examination, and other laboratory/imaging findings (i.e., outcomes data in a broader sense).

8. The Sample Size for the Training Set

The document does not specify a separate "training set" or "training set size." Immunoassays like ELISA kits are typically developed and optimized through laboratory research and development, rather than machine learning training on a discrete dataset in the way an AI algorithm might be. The performance data presented (precision and comparative testing) pertains to the validation of the finalized device.

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

Since there is no explicitly mentioned "training set" in the context of machine learning, the concept of establishing ground truth for a training set does not directly apply. The development of an ELISA kit involves selecting and optimizing reagents, antigen concentrations, and establishing a cutoff value. This iterative process of optimization would rely on known positive and negative controls and clinically characterized samples to ensure the assay performs as intended. However, the specific methods for establishing ground truth during this development phase are not detailed in this 510(k) summary.

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