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The EUROIMMUN Anti-PLA2R ELISA (IgG) test kit is intended for the qualitative or semiquantitative determination of IgG class autoantibodies against phospholipase A2 receptor (PLA2R) in human serum. It is used as an aid in the diagnosis of primary membranous glomerulonephritis (pMGN), in conjunction with other laboratory and clinical findings.

The EUROIMMUN Anti-PLA2R ELISA (IgG) consists of a microwell ELISA plate coated with PLA2R antigen, 5 calibrators, positive and negative control, peroxidase-labelled anti-human IgG conjugate, sample buffer, wash buffer concentrate, TMB chromogen/substrate solution and stop solution.

The acceptance criteria and study proving the device meets them are detailed below for the EUROIMMUN Anti-PLA2R ELISA (IgG).

1. Table of Acceptance Criteria and Reported Device Performance

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The EUROIMMUN Anti-PLA2R IFA is intended for the qualitative determination of IgG class autoantibodies against phospholipase A2 receptor (PLA2R) in human serum. It is used as an aid in the diagnosis of primary membranous glomerulonephritis (pMGN), in conjunction with other laboratory and clinical findings.

The kit (for 50 determinations) contains an instruction booklet and the following materials:

• . Slides, each containing 5x2 BIOCHIPs coated with PLA2R-transfected and controltransfected cells
• Fluorescein-labelled anti-human IgG (goat), ready for use (1 x 1.5 ml);
• Positive control: anti-PLA2R, ready for use (1 x 0.1 ml) ●
• . Negative control: autoantibody negative, ready for use (1 x 0.1 ml)
• Salt for PBS pH 7.2 (x2)
• Tween 20 (2 x 2.0 ml) .
• Embedding medium, ready for use (1 x 3.0 ml) •
• . Cover glasses (62 mm x 23 mm) (x12)

The EUROIMMUN IFA is an assay for standardized detection of anti-PLA2R antibodies utilized in laboratories familiar with indirect immunofluorescence. The test kit consists of slides, which contain BIOCHIPs coated with PLA2R transfected cells and control-transfected cells, fluorescein-labelled anti-human IgG (goat), a positive control for anti-PLA2R, a negative control. a salt for preparation of PBS. Tween 20, embedding medium, cover glasses and an instruction booklet.

This document describes the acceptance criteria and the studies performed to evaluate the performance of the EUROIMMUN Anti-PLA2R IFA for the qualitative determination of IgG class autoantibodies against phospholipase A2 receptor (PLA2R) in human serum, as an aid in the diagnosis of primary membranous glomerulonephritis (pMGN).

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria for analytical performance validation focused on qualitative results and fluorescence intensity deviation. For clinical performance, the acceptance criteria are implied by the reported clinical sensitivity and specificity for pMGN and control groups.

The reported device performance generally met or exceeded the implied acceptance criteria for analytical and clinical performance. The consistent qualitative results and controlled fluorescence intensity deviations in precision studies, along with the high specificity and reasonable sensitivity in clinical studies, support the device's intended use.

2. Sample sizes used for the test set and data provenance

• Analytical Performance Test Sets:

  • Intra-assay reproducibility: 6 characterized positive and negative serum samples, with 10 determinations each.
  • Inter-assay reproducibility: 6 characterized positive and negative serum samples, with 10 determinations each using two slides per run at five different times.
  • Lot-to-lot reproducibility: 2 sets of samples (6 samples per set: 2 negatives, 4 positives; and 2 negatives, 2 positives), tested with 3 different slide lots and 3 reagent lots respectively.
  • Site-to-site reproducibility: 7 characterized positive and negative serum samples, tested at 3 different sites, each with 2 runs per day for 5 days.
  • Interference: 3 serum samples (intensities 0, 1, 3), tested with 3 different concentrations of each interfering substance.
  • Cross-reactivity: Panel of 60 clinically characterized sera.
  • Assay Cut-off: 35 biopsy-proven pMGN patients, 182 non-membranous glomerulonephritis patients, and 150 normal healthy blood donors.

• Clinical Performance Test Set: 560 clinically characterized samples (275 from pMGN patients, 285 from control groups including sMGN, non-membranous glomerulonephritis, SLE, SSc, PSA, RA, Thyroiditis).

• Expected Values/Reference Range: 128 samples from normal healthy European population and 189 samples from normal healthy US population.

• Data Provenance: The document does not explicitly state the country of origin for all samples. However, for the reference range, it specifies "normal healthy European population" and "normal healthy US population." The clinical samples are described as "clinically characterized samples," often associated with patient cohorts from studies, which could be retrospective or prospective. The context of "samples drawn within 8 weeks after biopsy, before treatment" for pMGN patients and exclusion of "patients who had been or were currently being treated with immunosuppressive drugs" suggests retrospective collection from specific patient groups that fit these criteria at the time of collection.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

• Analytical Performance: For site-to-site reproducibility, "each result was evaluated by two different technicians independently." Qualifications for these technicians are not provided.
• Clinical Performance:
  • Ground Truth for pMGN: "pMGN diagnosis was based on renal biopsy and was considered to be idiopathic/primary when no secondary cause of MGN was suspected on the basis of clinical and laboratory criteria." The number and qualifications of experts (e.g., pathologists, nephrologists) who rendered these diagnoses are not specified.
  • Ground Truth for sMGN: "sMGN diagnosis was based on serological tests and clinical evaluation." The number and qualifications of experts are not specified.
  • Ground Truth for other control groups: Diagnosis was based on established diagnostic criteria and clinical evaluation. The number and qualifications of experts are not specified.
• Assay Cut-off: Ground truth was based on "biopsy proven pMGN patients," "non-membranous glomerulonephritis patients," and "normal healthy blood donors," implying clinical and pathological diagnoses, but expert details are not specified.

4. Adjudication method for the test set

• Analytical Performance: For site-to-site reproducibility, "Each result was evaluated by two different technicians independently." This implies a form of independent double-reading. However, explicit adjudication rules (e.g., how discrepancies were resolved, 2+1, 3+1, none) are not provided.
• Clinical Performance: No explicit adjudication method is described for establishing the clinical ground truth diagnoses (e.g., for pMGN, sMGN, or control groups). The diagnoses were established based on biopsy, serological tests, and clinical evaluation, but there is no mention of blinded review or consensus processes by multiple experts for the clinical ground truth.

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

• A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This device is an Indirect Immunofluorescent Antibody Assay (IFA), which is a diagnostic laboratory test that relies on laboratory technicians for interpretation of fluorescence intensity under a microscope, rather than an AI system assisting human readers. The context provided does not involve AI assistance.

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

• This is not an algorithm-only device. It is an IFA kit for laboratory use. While internal scoring of fluorescence intensity is mentioned, the evaluation of fluorescence and subsequent qualitative or quantitative reporting is performed by laboratory technicians using a fluorescent microscope. The device itself does not perform automated image analysis or diagnosis without human intervention.

7. The type of ground truth used

• Analytical Performance: The ground truth for analytical performance studies generally relied on pre-characterized serum samples (e.g., known positive or negative, with defined fluorescence intensities).
• Assay Cut-off Validation: Ground truth was primarily based on histopathological diagnosis (renal biopsy) for pMGN, and clinical diagnosis with laboratory findings for non-membranous glomerulonephritis and normal healthy individuals.
• Clinical Performance:
  • Primary Membranous Glomerulonephritis (pMGN): Diagnosis was primarily based on renal biopsy findings, supplemented by clinical and laboratory criteria to rule out secondary causes. This is a form of pathology-based ground truth combined with clinical evaluation.
  • Secondary Membranous Glomerulonephritis (sMGN): Diagnosis was based on serological tests and clinical evaluation.
  • Other Control Groups: Diagnoses were based on established diagnostic criteria and clinical evaluation.

8. The sample size for the training set

• No explicit training set is mentioned in the context of an algorithm or AI model. This device is a traditional IFA assay. The closest equivalent to "training" in this context would be the data used to validate the assay parameters, such as the initial establishment of the assay cut-off. For the assay cut-off, the sample size used was 35 pMGN patients, 182 non-membranous glomerulonephritis patients, and 150 normal healthy blood donors.

9. How the ground truth for the training set was established

• As there is no "training set" in the AI sense for this traditional IFA assay, the question refers to how ground truth was established for the samples used to determine the assay cut-off and validate its performance.
• Assay Cut-off Establishment:
  • pMGN samples: Ground truth was "biopsy proven pMGN patients." This refers to a pathology-based diagnosis established by medical professionals.
  • Non-membranous glomerulonephritis patients: Ground truth was their clinical diagnosis.
  • Normal healthy blood donors: Ground truth was their healthy status confirmed by medical screening, not having the disease markers.

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