(29 days)
The CoaguChek XS Plus System is intended for use by professional healthcare providers for quantitative prothrombin time testing for the monitoring of warfarin therapy. The system uses fresh capillary or non-anticoagulated venous whole blood.
The CoaguChek XS Plus system is a portable coagulation monitoring system to monitor prothrombin time (PT) in patients receiving oral anticoagulant therapy. The system uses the amperometric detection of thrombin in the blood sample. A test strip is used to determine a PT value from 10 uL of whole blood. Onboard quality control is available on every test strip and the system also features an optional external quality control material (CoaguChek XS PT Control).
Here's a breakdown of the acceptance criteria and study information for the CoaguChek XS Plus System, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The submission does not explicitly state "acceptance criteria" as a separate, quantified set of thresholds for each performance metric. Instead, it presents performance characteristics (e.g., accuracy, precision) of the new CoaguChek XS Plus System and compares them directly to the predicate device (CoaguChek XS System) to demonstrate substantial equivalence. The implication is that the performance of the new device is comparable to, or as good as, the predicate device.
| Performance Metric | Acceptance Criteria (Implied: Comparable to Predicate) | CoaguChek XS Plus System Performance | Predicate Device (CoaguChek XS) Performance |
|---|---|---|---|
| Accuracy (Venous Blood vs. Lab Reference) | Comparable to Predicate | N = 811 | |
| Slope = 1.090 | |||
| Intercept = -0.2 | |||
| Correlation = 0.974 | N = 710 | ||
| Slope = 1.034 | |||
| Intercept = -0.02 | |||
| Correlation = 0.974 | |||
| Accuracy (Capillary Blood vs. Lab Reference) | Comparable to Predicate | N = 822 | |
| Slope = 1.075 | |||
| Intercept = -0.1 | |||
| Correlation = 0.972 | N = 700 | ||
| Slope = 1.006 | |||
| Intercept = 0.032 | |||
| Correlation = 0.971 | |||
| Whole Blood Precision (Venous) | Comparable to Predicate | N = 399 | |
| Mean INR = 2.32 | |||
| SD = 0.046 | |||
| CV = 2.00 | N = 357 | ||
| Mean INR = 2.59 | |||
| SD = 0.06 | |||
| CV = 2.42 | |||
| Whole Blood Precision (Capillary) | Comparable to Predicate | N = 399 | |
| Mean INR = 2.26 | |||
| SD = 0.077 | |||
| CV = 3.39 | N = 344 | ||
| Mean INR = 2.59 | |||
| SD = 0.11 | |||
| CV = 4.35 | |||
| Control Precision (Level 1) | Comparable to Predicate | N = 538 | |
| Mean INR = 1.18 | |||
| SD = 0.04 | |||
| CV = 3.37 | N = 54 | ||
| Mean INR = 1.20 | |||
| SD = 0.01 | |||
| CV = 1.1 | |||
| Control Precision (Level 2) | Comparable to Predicate | N = 535 | |
| Mean INR = 2.95 | |||
| SD = 0.12 | |||
| CV = 4.10 | N = 54 | ||
| Mean INR = 2.49 | |||
| SD = 0.06 | |||
| CV = 2.3 | |||
| Hematocrit Range | Not significantly affect test results for 25-55% | Does not significantly affect test results for 25-55% | Same |
| Bilirubin | No significant effect up to 30 mg/dL | No significant effect up to 30 mg/dL | Same |
| Triglyceride (Lipemic samples) | No significant effect up to 500 mg/dL | No significant effect up to 500 mg/dL | Same |
| Hemolysis | No significant effect up to 1000 mg/dL | No significant effect up to 1000 mg/dL | Same |
| Heparin | Unaffected up to 0.8 U/mL | Unaffected up to 0.8 U/mL | Same |
| Low Molecular Weight Heparin | Insensitive up to 2 IU anti-factor Xa activity/mL | Insensitive up to 2 IU anti-factor Xa activity/mL | Same |
| Measuring Range | 0.8 to 8.0 INR | 0.8 to 8.0 INR | Same |
2. Sample Size Used for the Test Set and Data Provenance
- Accuracy (Venous Blood): N = 811
- Accuracy (Capillary Blood): N = 822
- Whole Blood Precision (Venous): N = 399
- Whole Blood Precision (Capillary): N = 399
- Control Precision (Level 1): N = 538
- Control Precision (Level 2): N = 535
Data Provenance: The document does not explicitly state the country of origin or if the data was retrospective or prospective. Given the nature of a 510(k) submission for a medical device that measures PT, these are typically prospective clinical studies conducted in a controlled environment to evaluate immediate device performance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document refers to "lab reference" for accuracy studies. This implies that standard laboratory methods for Prothrombin Time testing were used as the gold standard. However, it does not specify the number or qualifications of experts involved in performing these reference tests or establishing the ground truth. It's likely that certified medical laboratory technologists or similar professionals performed these reference tests.
4. Adjudication Method for the Test Set
Not applicable. This device measures a quantitative value (INR). Adjudication methods like 2+1 or 3+1 are typically used for qualitative or subjective assessments where multiple readers might interpret findings, for example, in image-based diagnostics. For quantitative measurements compared to a lab reference, such adjudication is not generally needed.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was Done
No, an MRMC comparative effectiveness study was not done. The CoaguChek XS Plus System is a device designed for quantitative measurement of prothrombin time, not for subjective interpretation by multiple readers like an imaging device. Therefore, the concept of human readers improving with or without AI assistance is not directly applicable in this context.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
Yes, the studies reported are standalone performance studies of the device. The "System Performance Characteristics" section reports the accuracy and precision of the CoaguChek XS Plus System itself, comparing its measurements to a "lab reference" or evaluating its internal consistency. This is the device's inherent performance without human interpretation influencing the final reported value beyond the act of operating the device and performing the test.
7. The Type of Ground Truth Used
The ground truth used for accuracy studies was a "lab reference." This indicates that the device's PT/INR measurements were compared against results obtained from established, likely hospital- or clinical laboratory-based reference methods for Prothrombin Time determination. This would typically involve trained technicians using calibrated laboratory instruments.
8. The Sample Size for the Training Set
The document does not provide information about a "training set" or its sample size. This is typical for a 510(k) submission for a device like the CoaguChek XS Plus, which is primarily an analytical measurement device. The device's underlying technology (electrochemical detection of thrombin activity) is well-established, and its "software" is focused on measurement processing and user interface features, rather than learning from a large dataset in the way a machine learning algorithm would. The "measurement software" is stated to be identical to the predicate, suggesting it's not a new algorithm "trained" on data.
9. How the Ground Truth for the Training Set Was Established
As no training set is mentioned or applicable in the context of this device's development as described, there is no information on how its ground truth would have been established. If any internal development iterations involved data, it would likely be against reference lab methods to ensure the electrochemical principle and measurement algorithms were correctly implemented.
§ 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).