(106 days)
The Rapidpoint Low range Heparin Management Test Card is to be used with the Rapidpoint Coag (formerly TAS) Analyzer to monitor the effects of low to moderate levels of unfractionated heparin on coagulation in noncitrated arterial whole blood samples from patients undergoing diagnostic and interventional procedures.
The test is for in vitro diagnostic use. It is especially suited for professional use in decentralized areas of the hospital near the patient's bedside, in the cardiac catheterization lab, and other areas where patients are treated with low to moderate levels of heparin.
The Rapidpoint LHMT provides a method to measure the response of a patient to heparin. A noncitrated whole blood sample can be used for this test. The test card has a magnetic stripe on the back, which encodes lot specific information such as number, expiration date, and mathematical factors specific to that lot. A room temperature test card is removed from the pouch and the card is passed through the card reader of the instrument to instrument to run a test. The instrument instructs the operator to insert a test card and then requests patient and sample information. The card is warmed and the operator is prompted to add a drop of blood to the card sample well. The sample flows into the card and rehydrates the reagent, which begins the reaction. As the reaction proceeds and clotting begins, the movement of the particles decreases, and the instrument signals the clotting time.
Here's an analysis of the provided text, focusing on acceptance criteria and the study that proves the device meets those criteria:
Device: Rapidpoint Low range Heparin Management Test (LHMT) Card
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state "acceptance criteria" in a quantitative, pass/fail manner. However, it does describe performance characteristics that were likely evaluated for market clearance. The primary evidence presented is the correlation to a predicate device.
| Performance Characteristic | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Linearity/Range | Linear response to heparin | Responds in a linear manner from 0 to 3.0 U/ml of heparin. |
| Sensitivity | Sensitive to heparin effects | Sensitive to the effects of heparin on coagulation. |
| Specificity | Insensitive to intrinsic/common coagulation pathway deficiencies, and certain interfering substances. | Relatively insensitive to deficiencies in the intrinsic and common coagulation pathways. Lipid (to at least 15 mg/ml), nitroglycerin (to 1 ug/ml), and Dextran (to 6 mg/ml) had no effect. |
| Temperature Effect | No effect of sample temperature | No effect of sample temperature (2 - 37°C). |
| Correlation to Predicate Device (ACT) | Substantially equivalent to predicate devices (ACT or ACT-LR) | Overall correlation of 0.93 of the LHMT card to the ACT (for noncitrated samples from all sites combined). |
| Normal Range | Establish normal range | Normal ranges (mean +/- 2 SD) were 65 to 175 seconds for noncitrated whole blood. Baseline samples from patients ranged from 53 to 195 seconds. |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size:
- Normal Donors: 120 (59 males, 61 females) for establishing normal ranges.
- Patient Samples: 429 samples from 232 individuals undergoing various treatments.
- Data Provenance:
- Normal Donors: "normal, healthy donors," likely gathered prospectively for this study.
- Patient Samples: "samples drawn from individuals expected to have abnormal LHMT results" undergoing "a variety of treatments." The description "Field testing and clinical testing were done at large hospitals" suggests these were prospective clinical studies in multiple locations. The document does not specify the country of origin, but given the submission to the FDA in the US, it's highly probable the studies were conducted in the US.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
The document does not mention the use of experts to establish a "ground truth" for the test set in the traditional sense of consensus reading or adjudication. The ground truth for the comparison was established by:
- Predicate Device Results: The results from the Hemochron ACT or ACT-LR device served as a comparative "ground truth" for assessing equivalence.
- Chromogenic Anti-Xa Assay: A chromogenic anti-Xa assay (Diagnostica Stago's Stachrom Heparin) was used as a "reference, tiebreaker method" to determine heparin concentration, which is a more direct measure of heparin activity.
Therefore, no panel of human experts was used for adjudication or establishing ground truth in the way one might see in image-based diagnostic studies.
4. Adjudication Method for the Test Set:
Not applicable in the context of this device. The study design involved comparing the LHMT device's quantitative output to established, quantitative measurements from a predicate device and a reference assay. There was no subjective interpretation that would require an adjudication method.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, What Was the Effect Size of How Much Human Readers Improve With AI vs Without AI Assistance:
No, an MRMC comparative effectiveness study was not done. This device is not an AI-assisted diagnostic tool for human interpretation; it's an automated in vitro diagnostic test for measuring coagulation time in the presence of heparin. Therefore, there's no "human reader" component to improve.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
Yes, the study described is a standalone performance study of the Rapidpoint LHMT device. The device itself performs the measurement, and the results are then compared to other quantitative measures (predicate device, reference assay). There is no "human-in-the-loop" interaction in the production of the primary diagnostic result from the LHMT card.
7. The Type of Ground Truth Used:
The ground truth for evaluating the LHMT device's performance was:
- Comparative Measurement: Results from the predicate device (Hemochron ACT or ACT-LR) for assessing substantial equivalence.
- Reference Method: Results from a chromogenic anti-Xa assay (Stachrom Heparin), which directly measures heparin concentration and served as a "reference, tiebreaker method." This provides a more objective, gold-standard-like measure of heparin activity.
8. The Sample Size for the Training Set:
The document describes nonclinical performance data ("Preclinical testing was done at CDI") and then clinical performance data. It does not explicitly separate data into "training" and "test" sets in the context of a machine learning or algorithm development paradigm. The "nonclinical performance data" could be considered part of the development/training phase, but no specific sample size is given for it. The clinical data (120 normal donors, 429 patient samples) are presented as the primary "test set" for demonstrating performance and substantial equivalence.
9. How the Ground Truth for the Training Set Was Established:
As mentioned in point 8, the concept of a "training set" with established ground truth as distinct from a "test set" isn't explicitly detailed as it would be for an AI algorithm.
- Preclinical Testing: The preclinical testing likely involved internal laboratory studies to characterize the device's basic performance (linearity, sensitivity, specificity, temperature effects). The "ground truth" for these studies would have been established through controlled experimental conditions, using known concentrations of heparin and other interfering substances, and comparing results to established laboratory methods or internal standards.
- Clinical Testing: For the clinical evaluation data presented, the "ground truth" for comparison was the measurements from the predicate device (ACT) and the reference anti-Xa assay.
§ 864.7140 Activated whole blood clotting time tests.
(a)
Identification. An activated whole blood clotting time tests is a device, used to monitor heparin therapy for the treatment of venous thrombosis or pulmonary embolism by measuring the coagulation time of whole blood.(b)
Classification. Class II (performance standards).