(193 days)
The CoaguChek System is intended for quantitative Prothrombin Time (PT) testing for monitoring of warfarin therapy, using fresh capillary or non-anticoagulated venous whole blood by professional healthcare providers.
The PT•S test strip is intended for quantitative prothrombin time (PT) testing for monitoring of warfarin therapy, using fresh capillary or non-anticoagulated venous whole blood with the CoaguChek System by professional health care providers. Blood coagulation is one of the body's protective responses. Blood clots (thrombi) form as a direct response to vessel injury, preventing excessive loss of blood. Certain disease conditions require oral anticoagulants, sometimes known as blood thinners. Warfarin, sometimes known as Coumadin®, is a commonly used anticoagulant. Patients on warfarin must be carefully monitored to ensure the anticoagulant level is maintained in the therapeutic range. One method for monitoring the anticoagulant level is by using the one-stage Prothrombin Time (PT) Test. The PT•S test strip uses a modified version of this method. The PT•S test strip, used as directed with the CoaguChek monitor, will accurately measure blood PT values. After placing a drop of fresh whole blood on the test strip, the blood is drawn into the reaction chamber and mixed with reagents that cause coagulation to begin. In the test strip, tiny iron particles are mixed with the sample. Alternating magnetic fields cause the iron particles to move within the sample. The endpoint is reached when the blood clot stops the iron particles from moving. The PT result is then displayed by the monitor.
Here's a breakdown of the acceptance criteria and study information for the PT•S Test Strips and Controls for the CoaguChek System, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The acceptance criteria are not explicitly stated as distinct pass/fail thresholds in the provided document. Instead, the submission demonstrates equivalence to the predicate device by comparing performance characteristics. For this reason, the "Acceptance Criteria" column below reflects the performance observed for the predicate device (ITC ProTime Microcoagulation System), which the PT•S system aims to be substantially equivalent to, and the "Reported Device Performance" shows the results for the PT•S system.
| Acceptance Criteria (Predicate Device Performance) | Reported Device Performance (PT•S Test Strips) |
|---|---|
| Precision with Controls | Level 1 (Mean INR 1.3 Controls): |
| Standard ProTime Cuvette: | Lot to Lot SD: 0.02 (%CV: 1.72) |
| Level I: within day 0.9 (SD 0.06) | Monitor to monitor SD: 0.01 (%CV: 0.95) |
| day to day 1.0 (SD 0.08) | Strip to strip SD: 0.04 (%CV: 3.32) |
| Level III: within day 3.2 (SD 0.19) | Total SD: 0.05 (%CV: 3.86) |
| day to day 3.2 (SD 0.12) | Level 2 (Mean INR 3.4 Controls): |
| ProTime 3 Cuvette: | Lot to Lot SD: 0.05 (%CV: 1.33) |
| Level I: within day 0.9 (SD 0.07) | Monitor to monitor SD: 0.08 (%CV: 2.22) |
| day to day 0.9 (SD 0.12) | Strip to strip SD: 0.13 (%CV: 3.79) |
| Level III: within day 4.0 (SD 0.19) | Total SD: 0.16 (%CV: 4.59) |
| day to day 4.2 (SD 0.22) | |
| Accuracy (Regression vs. Lab Plasma) | Venous Samples: |
| Standard ProTime Cuvette (Fingerstick): y=0.94x + 0.38 (r=0.95) | Regression Equation: y = 1.065x - 0.12 (Slope CI: 1.041, 1.090; Intercept CI: -0.19, -0.06; Correlation: 0.961) |
| Standard ProTime Cuvette (Venous): y=0.91x + 0.44 (r=0.94) | Capillary Samples: |
| ProTime 3 Cuvette (Fingerstick): y=1.05x + 0.07 (r=0.95) | Regression Equation: y = 1.089x - 0.17 (Slope CI: 1.058, 1.119; Intercept CI: -0.25, -0.09; Correlation: 0.958) |
| ProTime 3 Cuvette (Venous): y=0.97x + 0.19 (r=0.95) | |
| Normal Range | 99% of venous and capillary INRs ranged from 0.8 to 1.1 for 122 normal, healthy, warfarin-free individuals. |
| Reportable Range | 0.8 - 8.0 INR |
| Hematocrit Range | 32-52% (no significant effect) |
| Heparin Levels | Unaffected up to 2.0 U/mL heparin and insensitive to low molecular weight heparins up to 1 IU anti-factor Xa activity/mL (for PT•S, predicate stated "may be affected") |
Study Details
This submission describes standalone performance of the device, not a comparative effectiveness study with human readers.
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Sample Size Used for the Test Set and Data Provenance:
- Normal Range: 122 normal, healthy, warfarin-free individuals. Sample types: Venous and capillary. Data provenance: Not explicitly stated, but likely prospective to gather data specifically for this device's normal range. Country of origin not specified, but usually presumed US for FDA submissions unless otherwise stated.
- Precision with Controls: Two levels of liquid controls, three test strip lots, nine CoaguChek monitors. The number of replicates for each control level, monitor, and lot is detailed in the table. This is an internal study.
- Accuracy (Venous Samples): 610 venous samples collected from 309 outpatients. Data provenance: Prospective observational study at four external sites. Country of origin not specified.
- Accuracy (Capillary Samples): 448 capillary samples collected from 226 outpatients. Data provenance: Prospective observational study at three external sites. Country of origin not specified.
- Factor Sensitivity: Internal studies utilizing four replicates of each Factor Level (II, V, VII and X).
- Hematocrit Range: Internal studies, details on sample size not provided in the summary.
- Heparin Levels: Internal studies, details on sample size not provided in the summary.
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Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications:
- For the accuracy studies, the ground truth was established by laboratory plasma samples measured on an MLA 900 Analyzer using Ortho Recombiplastin. This is an automated laboratory instrument using a standardized reagent, implying no human expert "ground truth" per se. The device's performance is compared against this established laboratory method.
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Adjudication Method for the Test Set:
- Not applicable as the ground truth was an automated laboratory reference method, not human expert interpretation requiring adjudication.
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Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No. This is a medical device for measuring Prothrombin Time (PT) and INR, not an imaging or interpretive AI system that would typically involve human readers.
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Standalone Performance:
- Yes, the studies presented are for the standalone performance (algorithm only, though "algorithm" here refers to the device's measurement mechanism) of the PT•S test strips used with the CoaguChek monitor, without a human-in-the-loop component for result interpretation. Healthcare providers use the device, but the measurement itself is automated.
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Type of Ground Truth Used:
- Laboratory-based reference method: For accuracy, the PT•S system's results were compared to INR values obtained from venous plasma samples measured on an MLA 900 Analyzer using Ortho Recombiplastin. This is considered the gold standard or reference method for Prothrombin Time testing.
- For the normal range determination, individuals were classified as "normal, healthy, warfarin-free," which represents a clinical ground truth for typical INR values.
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Sample Size for the Training Set:
- The document does not explicitly mention a "training set" in the context of device development or algorithm training. This device appears to be based on a physical-chemical reaction and an electromechanical detection system, rather than a machine learning algorithm requiring a distinct training phase. Therefore, the concept of a "training set" as understood in AI/ML is not directly applicable here. The internal studies and method development would involve extensive testing and refinement, but not in the sense of an ML training set.
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How the Ground Truth for the Training Set Was Established:
- As noted above, a distinct "training set" and corresponding ground truth establishment process, as typically seen in AI/ML, is not described or implied for this type of device. The development and internal validation would have relied on established laboratory standards and comparisons to known PT values from various sources.
§ 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).