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The ASSERACHROM® tPA test kit is intended for the quantitative determination of tissue-type plasminogen activator (tPA) antigen in citrated plasma by the sandwich technique of enzyme immunoassay (EIA) known as enzyme-linked immunosorbent assay (ELISA).

The quantitative determination of tPA is generally performed during the assessment of the fibrinolytic system of a patient, for instance, following a thrombotic episode.

In addition, it has been reported that a high antigenic level of tPA is associated with a greater risk of myocardial infarction or vascular cerebral accident. Finally, quantitative tPA assays are useful in the detection of hypofibrinolytic and hyperfibrinolytic states.

The ASSERACHROM® tPA test kit is intended for the quantitative determination of tissue-type plasminogen activator (tPA) antigen in citrated plasma by the sandwich technique of enzyme immunoassay (EIA) known as enzyme-linked immunosorbent assay (ELISA).

Mouse monoclonal anti-tPA antibody is coated on the inside wall of a plastic microwell. The plasma to be tested is allowed to incubate in the microwell for two hours at room temperature, during which any tPA present is captured by the monoclonal antibody. Next, a second (and different) mouse monoclonal anti-tPA antibody coupled with peroxidase is added to the microwell for another 2-hour incubation at room temperature; this antibody-enzyme conjugate binds to another antigenic determinant of the tPA molecule that is already bound to the microwell in the first incubation step. The bound enzyme is revealed by its action on orthophenylenediamine in the presence of hydrogen peroxide to produce a yellow color; after addition of a strong acid to stop the enzymatic action, the intensity of the color developed bears a direct relationship to the tPA level initially present in the test plasma.

The kit provides sufficient reagents to perform 96 tests in micro-ELISA plate format. Reagents in intact (unopened) kits remain stable for 18 months after their date of manufacture, when stored at 2°-8°C. Reconstituted reagent stabilities are as follows: Reagent ● (antibody-coated microwell strips) must be used immediately after opening of its package; Reagent @ (anti-tPA-Peroxidase), 24 hours at 2°-8°C; Reagent Oa (ortho-Phenylenediamine) dissolved together with Reagent Ob (Urea Peroxide), 1 hour at room temperature (18°-25°C); 1:10 diluted Reagent © (Dilution Buffer) and 1:20 diluted Reagent ® (Washing Solution), 15 days at 2°-8°C, when free of any contamination; both the Reagent ® (tPA Calibrator) and Reagent ® (tPA Control), 4 hours at 20°C.

The ASSERACHROM® tPA reagent system has a detection limit of 1 ng/ml; a working range from 1 ng/ml up to the tPA level of Reagent ® (tPA Calibrator, up to 50 ng/ml); intra-assay reproducibility of < 6.5%; inter-assay reproducibility of < 8%.

The device concerned is the ASSERACHROM® tPA Test Kit, an ELISA-based assay for the quantitative determination of tissue-type plasminogen activator (tPA) antigen in citrated plasma.

Acceptance Criteria and Reported Device Performance

Study Information

The provided document, K971519, is a 510(k) premarket notification for the ASSERACHROM® tPA Test Kit. This notification outlines the device's characteristics and claims substantial equivalence to a predicate device.

Based on the provided text, a formal "study" proving the device meets the acceptance criteria in the sense of a clinical trial with human subjects is not detailed. Instead, the performance characteristics (detection limit, working range, and reproducibility) are stated as inherent properties of the assay and likely derived from internal validation studies conducted by the manufacturer. The document is a summary of these characteristics intended for regulatory submission.

Here's an analysis of the requested information based on the provided text:

1. Sample size used for the test set and the data provenance:

   • The document does not specify sample sizes for test sets used to determine the reported performance metrics (detection limit, working range, reproducibility).
   • Data provenance is not provided (e.g., country of origin, retrospective or prospective). These performance specifications are typically derived from in-vitro laboratory experiments.

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

   • Not applicable for this type of in-vitro diagnostic device performance characterization. "Ground truth" for analytical performance metrics like detection limit and reproducibility is established through controlled laboratory experiments, not expert interpretation of results.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

   • Not applicable. This concept is relevant for studies involving human interpretation or clinical outcomes, not for the analytical performance characteristics of an ELISA kit.

4. 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:

   • Not applicable. This is an in-vitro diagnostic kit, not an AI-assisted diagnostic tool. Therefore, MRMC studies and the concept of "human readers improve with AI" are not relevant.

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

   • The reported performance metrics (detection limit, working range, reproducibility) are inherently "standalone" in the sense that they describe the algorithm/kit's analytical capabilities without human interpretative intervention in the measurement itself (though human operation is required). There is no "algorithm only" in the context of an ELISA kit, as it's a biochemical assay.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • For analytical performance data like detection limit and reproducibility, the "ground truth" is defined by the known concentrations of standards or controls used in the assay and the statistical methods applied to the experimental results. It's based on biochemical and analytical principles, not clinical ground truth like pathology or outcomes.

7. The sample size for the training set:

   • Not applicable. This is not a machine learning or AI device that requires a training set. The assay's parameters (reagent concentrations, incubation times, etc.) are developed through biochemical optimization, not statistical training on a data set in the AI sense.

8. How the ground truth for the training set was established:

   • Not applicable, as there is no "training set" in the context of an ELISA kit. The "ground truth" for optimizing the assay would be based on achieving optimal signal-to-noise ratios, linearity, sensitivity, and specificity through experimental design and validation using known concentrations of tPA.

In summary, the provided text describes the analytical performance characteristics of a laboratory test kit and its claim of substantial equivalence for regulatory purposes. It does not detail a clinical study with elements like human readers, AI, or specific patient sample sizes that would typically be seen in the context of medical imaging or AI-driven diagnostic devices.

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