(124 days)
The Immedia System is an in vitro diagnostic device that provides quantitative prothrombin time (PT) results, expressed in seconds and INR units. It uses fresh capillary whole blood. It is intended for use by health care professional at the point of care to monitor patients who are on warfarin-type (coumarin) anticoagulation therapy. The device is not intended to be used for screening purposes.
The Immedia™ Prothrombin Time System measures the Prothrombin Time (PT) of fresh capillary whole blood. The test is performed by inserting a test strip into the meter and applying a drop of blood to the sample receptacle of the test strip. The meter automatically performs the PT test and the result is displayed as International Normalized Ratio (INR) and seconds (PT). The meter automatically stores all test results in memory. The device is powered by batteries and/or AC adapter. The disposable strip contains a rotating, spoked wheel that draws the sample into the reaction well after it is applied to the sample receptacle. The spokes rotate across the path of an infrared light beam and mix the liquid sample with the thromboplastin which is dried in the reaction well. When the sample clots, the clot is picked up by the spokes, interrupting the path of the infrared light beam that is detected by the meter. A separate Calibration Strip is used for inputting the calibration data. High Control and Low Control Strips are also provided for quality control purposes.
The provided text describes the Immedia Prothrombin Time System, a device for measuring Prothrombin Time (PT) and International Normalized Ratio (INR) in fresh capillary whole blood, intended for monitoring patients on warfarin-type anticoagulation therapy.
Here's an analysis of the acceptance criteria and the study information:
1. Table of Acceptance Criteria and Reported Device Performance:
The document states the device was compared to the predicate device (Roche CoaguChek S) and a reference method, with the accuracy found to be "equivalent (r>0.90)." It also mentions that "Precision and linearity evaluations were performed on the Immedia device and the results were found to be acceptable." Specific numerical acceptance criteria for precision and linearity are not provided.
| Metric | Acceptance Criteria (Stated or Implied) | Reported Device Performance |
|---|---|---|
| Accuracy (r) | r > 0.90 (vs. predicate and reference) | r > 0.90 (found to be equivalent) |
| Precision | Acceptable (implied) | Acceptable |
| Linearity | Acceptable (implied) | Acceptable |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not explicitly stated in the provided text for the accuracy studies. The document only mentions "field studies."
- Data Provenance: Not explicitly stated (e.g., country of origin, retrospective or prospective). The term "field studies" suggests prospective data collection in a real-world setting.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
Not applicable. This device is an in-vitro diagnostic system that measures a physiological parameter (PT/INR) which typically has a gold standard measurement technique or a reference method. It does not rely on expert interpretation of images or other subjective data for ground truth establishment.
4. Adjudication Method:
Not applicable, as expert ground truth establishment is not relevant for this device.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
Not applicable. This is an in-vitro diagnostic device that provides quantitative results, not an imaging device requiring human reader interpretation with or without AI assistance.
6. Standalone Performance Study:
Yes, a standalone performance study was done for the algorithm (device). The "Summary of performance data" section indicates that the accuracy, precision, and linearity of the Immedia device were evaluated independently. While the accuracy was compared to a predicate and reference method, the precision and linearity evaluations were performed on the Immedia device itself, implying standalone testing.
7. Type of Ground Truth Used:
The ground truth for the accuracy study was established by comparison to a reference method and the predicate device (Roche CoaguChek S). For precision and linearity, the ground truth would be statistical measures inherent to the device's ability to consistently and accurately measure across a range.
8. Sample Size for the Training Set:
Not applicable. This device is a measurement system and not described as using machine learning or AI that would require a "training set" in the conventional sense. Its performance is based on its mechanical, chemical, and optical design, not on a learned algorithm.
9. How the Ground Truth for the Training Set Was Established:
Not applicable, as no training set (in the AI/ML context) is mentioned or implied for this device.
§ 864.5425 Multipurpose system for in vitro coagulation studies.
(a)
Identification. A multipurpose system for in vitro coagulation studies is a device consisting of one automated or semiautomated instrument and its associated reagents and controls. The system is used to perform a series of coagulation studies and coagulation factor assays.(b)
Classification. Class II (special controls). A control intended for use with a multipurpose system for in vitro coagulation studies is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 864.9.