(63 days)
The HemoSense INRatio is an in vitro diagnostic system that provides a quantitative prothrombin time results, expressed in seconds and as an International Normalized Ratio (INR). It uses fresh capillary whole blood and is intended for use by health care professionals in monitoring patients who are on warfarin-type (coumarin) anticoagulation therapy. This device is not intended to be used for screening purposes.
The INRatio Prothrombin Time Monitoring System uses a modified version of the one-stage prothrombin time test. After a drop of blood is applied to the test strip, it is drawn into the test area and mixed with reagents that cause coagulation to begin. The test area on the test strip is separated into three channels, each of which contains electrodes for detection of the blood clot. One channel contains the reagents to perform the prothrombin time test on the blood sample. The other two channels contain the reagents to run control tests. No external quality control tests are required for the INRatio System. The meter monitors the reactions, and calculates the PT and INR for the blood sample, which are reported on the display. If the control results are not within a set range, it indicates a problem with the test and an error message is reported on the display instead of a result.
The provided document describes the INRatio Prothrombin Time Monitoring System (K020679) and its substantial equivalence to a predicate device, the Roche CoaguChek S. However, it does not provide detailed acceptance criteria and a structured study report with the specific information requested in your prompt.
The document is a 510(k) summary for premarket notification, which focuses on demonstrating substantial equivalence, not necessarily on presenting a comprehensive study report with quantitative acceptance criteria as you've outlined.
Here's a breakdown of what can be inferred or is explicitly stated from the provided text, and what information is missing:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Accuracy (compared to predicate and reference method) | "found to be equivalent (r>0.90)" |
| Precision | "were found acceptable" |
| Linearity | "were found acceptable" |
| Interfering Substances | "performed and the results are reflected in the product labeling" |
| Hematocrit | "performed and the results are reflected in the product labeling" |
Missing Information:
- Specific quantitative thresholds for "acceptable" precision and linearity. The document only states they were "found acceptable."
- Details of the reference method used for accuracy comparison.
2. Sample size used for the test set and the data provenance:
- Sample Size: Not explicitly stated for any of the tests (accuracy, precision, linearity).
- Data Provenance: The studies were described as "field studies." The country of origin is not specified, but the applicant (HemoSense, Inc.) and the FDA are in the USA. It's not explicitly stated if the data was retrospective or prospective. Given it's a "field study," it's likely prospective data collection for device evaluation.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Missing Information. The document does not describe the use of experts to establish ground truth for the test set. The ground truth for Prothrombin Time devices is typically established through a reference laboratory method or a predicate device.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Missing Information. No mention of an adjudication method is made.
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:
- This is not applicable to the INRatio device. The INRatio is an in vitro diagnostic device for quantitative Prothrombin Time measurement, not an AI-assisted diagnostic imaging or interpretation system requiring human readers or affecting their performance. The device directly calculates and reports PT/INR values.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, implicitly. The context of the INRatio system, as an in vitro diagnostic device that calculates and displays results, inherently refers to its standalone performance. The accuracy, precision, and linearity tests would assess the device's performance in generating these results independently.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- For accuracy, the device was compared to the predicate device CoaguChek S and a "reference method." While the specific "reference method" isn't detailed, for PT/INR testing, this typically refers to a laboratory-based coagulation analyzer (e.g., automated photo-optical clot detection instruments). This would be considered a reference laboratory method or a calibrated gold standard.
8. The sample size for the training set:
- Missing Information. The document does not discuss a "training set" in the context of machine learning or AI. This device is electro-mechanical and reagent-based, not an AI model that undergoes a training phase.
9. How the ground truth for the training set was established:
- Not applicable. As explained in point 8, there is no "training set" for this type of device.
Summary of Limitations in the Provided Document:
The provided text is a 510(k) summary, which serves to establish substantial equivalence. It highlights key performance aspects like accuracy, precision, and linearity as "acceptable" or "equivalent," but it lacks the granular detail of a full study report (e.g., specific sample sizes for each test, detailed methodology for ground truth establishment, quantitative acceptance criteria thresholds, or raw/processed data). This information would typically be found in the full 510(k) submission, not necessarily in the public summary.
§ 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).