(422 days)
The Hemochron® Jr. Citrated PT is a unitized microcoagulation test intended for in vitro diagnostic use in performing a quantitative, one-stage prothrombin time. The Citrated PT test is performed using a citrated whole blood sample on the Hemochron® Jr. microcoagulation system. The instrument is portable and is intended for point of care testing. The instrument is not intended for home use. For in vitro Diagnostic Use
The Hemochron® Jr. Microcoagulation Citrated PT test is a self-contained disposable test cuvette, prefilled with dried reagents required to perform a PT using citrated whole blood with the Hemochron® Jr. Whole Blood Microcoagulation System. The thromboplastin employed in the Hemochron® Jr. Microcoagulation Citrated PT test is identical to that used in the predicate device, the ITC Microcoagulation Prothrombin Time Test. The difference between the current assay and the predicate is a reagent modification to include calcium salt such that citrated whole blood may be used as the test substrate. The predicate device uses only fresh, non-citrated whole blood. In addition to the calcium salt, the preparation contains rabbit brain thromboplastin, stabilizers and buffers, similar to the reagents contained in the predicate device. The Hemochron® Jr. Microcoagulation Citrated PT and the predicate ITC Microcoagulation Prothrombin Time Test are both intended for point-of-care use. Both assays are performed using the ITC Microcoagulation analyzers.
The provided document describes the Hemochron® Jr. Microcoagulation Citrated PT test, a device intended for in-vitro diagnostic use to perform a quantitative, one-stage prothrombin time for monitoring patients receiving oral anticoagulant therapy.
Here's an analysis based on the supplied text:
Acceptance Criteria and Reported Device Performance
The document does not explicitly state numerical acceptance criteria in a table format. However, it indicates that the device's performance was evaluated against laboratory standards and a predicate device.
| Performance Characteristic | Acceptance Criteria (Implicit/Inferred) | Reported Device Performance |
|---|---|---|
| Sensitivity to Vitamin K dependent coagulation factors | High correlation to laboratory (plasma-based) assay. | Dose-response curves were obtained and highly correlated to the laboratory (plasma-based) assay. As the coagulant factor level decreased below 40%, the Citrated PT result began to prolong above the normal range. |
| Correlation with laboratory PT-INR results (Clinical Comparison) | High degree of correlation. | Demonstrated a high degree of correlation of the Hemochron Jr. Citrated PT-INR result and laboratory PT-INR results. |
| Precision | Not explicitly stated. | Between 1% and 7% across different operators and test days (using whole blood controls). |
| Substantial Equivalence | To the predicate device and standard laboratory plasma PT assay. | The thromboplastin is identical to the predicate. Reagent modification includes calcium salt (for citrated blood). Results are displayed as INR and plasma PT equivalent. |
Study Details:
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Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: Not explicitly stated. The document mentions "clinical correlation studies" and "laboratory studies" that were conducted, but does not provide specific numbers for patient samples or controls.
- Data Provenance: The "clinical comparisons to the laboratory assay were conducted at three university medical centers." The country of origin is implicitly the USA, given the FDA submission. The studies were likely prospective clinical comparisons based on the nature of "clinical correlation studies."
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Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Not specified in the provided text. The "ground truth" for correlation studies was the "laboratory (plasma-based) assay" and "laboratory PT-INR results," implying standard clinical laboratory procedures and established reference methods.
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Adjudication Method for the Test Set:
- Not applicable as the ground truth appears to be based on established laboratory assays rather than expert consensus on interpretations.
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Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No. This type of study (comparing human readers with and without AI assistance to improve diagnostic accuracy) is not relevant for this device, which is an in-vitro diagnostic test.
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Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study:
- Yes, implicitly. The device itself is an automated analyzer that performs the test and displays results (INR and plasma PT equivalent) without human interpretation of raw data. The studies focused on the accuracy and precision of the device's output compared to laboratory standards.
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Type of Ground Truth Used:
- Laboratory Assay Results: The primary ground truth was the "laboratory (plasma-based) assay" and "laboratory PT-INR results," which are recognized clinical standards for measuring coagulation.
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Sample Size for the Training Set:
- Not applicable. This device is a diagnostic test kit and analyzer, not an AI/machine learning algorithm that requires a "training set" in the conventional sense. The "training" would involve reagent formulation and instrument calibration based on known concentrations/levels, but specific sample sizes for this are not provided.
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How the Ground Truth for the Training Set Was Established:
- Not applicable for a training set in the AI sense. For the development and calibration of the assay, the ground truth would have been established through standard biochemical and clinical laboratory methods, using reference materials and established PT/INR measurements.
§ 864.7750 Prothrombin time test.
(a)
Identification. A prothrombin time test is a device used as a general screening procedure for the detection of possible clotting factor deficiencies in the extrinsic coagulation pathway, which involves the reaction between coagulation factors III and VII, and to monitor patients receiving coumarin therapy (the administration of one of the coumarin anticoagulants in the treatment of venous thrombosis or pulmonary embolism).(b)
Classification. Class II (performance standards).