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The Chrono-log WBA, Model 591/592 is intended for determination of platelet function in a whole blood specimen.

The Chrono-log WBA, Model 591/592 uses electrical impediance to measure platelet aggregation in a whole blood sample. The Impedance is measured using an electrode with two platinum alloy wires. A small voltage is applies across these two wires. When the electrode is placed into a diluted whole blood specimen and a monolayer is formed around the two wires. In the absence of an agonist, the platelet build-up stabilizes and a baseline is established. When an agonist is added to the specimen, the platelets begin to aggreazate and collect on the electrode wires causing a change in impedance. The change of impedance is directly proportional to the amount of Aggregation in the specimen. The change of impedance is displayed on a front panel readout. An analog output which, when connected to a strip chart recorder, provides an aggregation curve. Model 591 is a single channel version; Model 592 is the duel channel version.

The provided 510(k) summary for the Chrono-log Whole Blood Aggregometer (WBA), Model 591/592, does not contain the detailed information required to answer many of your specific questions regarding acceptance criteria and the comprehensive study design.

This document primarily focuses on establishing substantial equivalence to previously cleared devices (Chrono-log Whole Blood Aggregometer K830749 and Centocor AggreStat K954997) rather than providing a standalone performance study with explicit acceptance criteria.

However, I can extract the information that is present and indicate where the requested details are missing.

Here's a breakdown of the available information and the missing details:

1. A table of acceptance criteria and the reported device performance

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Sample Size for Test Set: Not specified in the provided document.
• Data Provenance: Not specified in the provided document. It only mentions "tests data included in this application."
• Retrospective or Prospective: Not specified in the provided document.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

• Number of Experts: Not applicable/Not specified. For a device measuring a physiological parameter like platelet aggregation, the "ground truth" would likely be derived from the existing, validated methods (e.g., light transmission aggregometry, or the predicate devices themselves) rather than expert consensus on interpretation.
• Qualifications of Experts: Not applicable/Not specified.

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

• Adjudication method: Not applicable/Not specified. Adjudication methods are typically used in studies where human interpretation of results is a primary outcome, such as imaging studies. For a device measuring a quantitative physiological parameter, adjudication of an expert consensus on a subjective finding is generally not relevant.

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

• MRMC Comparative Effectiveness Study: No. This type of study is not relevant for this device. The Chrono-log WBA is a diagnostic device that directly measures platelet aggregation; it does not involve human readers interpreting images or data for diagnosis in a way that AI assistance would "improve" their performance.

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

• Standalone Performance: Yes, in principle. The Chrono-log WBA is a standalone device that provides a measurement (change in impedance reflecting aggregation). Its performance would be evaluated on its ability to accurately and precisely make this measurement, rather than as an "algorithm only" component of a larger system. The document, however, does not provide the specific results of such a standalone performance study, only that it was found substantially equivalent to predicate devices.

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

• Type of Ground Truth: Not explicitly stated, but it would most likely be:
  • Comparison to predicate devices: The primary ground truth for establishing substantial equivalence would be the measurements obtained from the predicate devices (Chrono-log Whole Blood Aggregometer K830749 and Centocor AggreStat K954997) or other established methods for measuring platelet aggregation (e.g., Light Transmission Aggregometry).
  • Clinical correlation: While not detailed in this summary, the "ground truth" for the predicate devices and the underlying science of platelet aggregation measurement relies on clinical correlation with platelet function and bleeding disorders.

8. The sample size for the training set

• Sample Size for Training Set: Not applicable/Not specified. This device does not appear to be an AI/machine learning-based device that would require a separate "training set" in the conventional sense. Its function is based on direct electrical impedance measurement.

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

• How Ground Truth for Training Set was Established: Not applicable. As noted above, this does not appear to be an AI/machine learning device.

Summary of Limitations of the Provided Document:

The provided 510(k) summary is extremely high-level and serves the purpose of demonstrating substantial equivalence. It lacks the detailed study methodology, performance metrics, and specifics about data collection that would be present in a comprehensive study report or a more detailed technical submission. It relies on the assertion that "examining the tests data included in this application" led to the finding of substantial equivalence, without providing those details in this public summary.

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