(71 days)
The new TAS aPTT Controls are intended to be used with the TAS Analyzer and aPTT cards, cleared by the FDA, to provide a method for quality control of the system. The controls produce clotting times which must be within accepted, standard ranges, to indicate that the analyzer and test cards are functioning properly and thereby help assure the accuracy of aPTT test results. The controls are substantially equivalent in intended use to other controls used in coagulation assays.
The controls for TAS aPTT cards consists of two separate vials. One was designed to mimic a sample from a normal individual, and the second to mimic a sample from a patient with a clotting factor deficiency of the intrinsic or common coagulation pathway. These controls are made with human plasma screened for antibodies to and antigens of human immunodeficiency and hepatitis viruses. To make the controls as easy to use as possible for point-of-care testing, we chose the patented packaging system of EDItek. This consists of a closed, crushable glass ampule containing lyophilized plasma which is inside a plastic sleeve. The sleeve contains water for diluent and has a capped dropper top with a filter tip. The entire assembly is shrink wrapped with a label and plastic seal. To use, the ampule is crushed inside the plastic sleeve, which allows the diluent to mix with the lyophilized plasma. The mixture is reconstituted by shaking or vortexing the capped vial. The plastic seal and cap are removed, two drops of plasma are discarded into a biohazard waste container, and a drop of the plasma suspension is added to a TAS aPTT test card in an analyzer. The rest of the test procedure and the manner of signal production is identical to that for a patient sample.
This PAC summary is based on the provided text, which appears to be a regulatory submission for a medical device (TAS aPTT Controls). The information is primarily focused on demonstrating substantial equivalence to a predicate device rather than a comprehensive study report with detailed acceptance criteria and standalone performance metrics typically found in AI/ML device studies.
1. Table of acceptance criteria and the reported device performance
Based on the provided text, the primary acceptance criteria for the TAS aPTT Controls are related to their ability to provide clotting times that are comparable to a legally marketed predicate device (Ci-trol; Dade; Baxter Diagnostics, Inc.) and to fall within established standard ranges. The device performance is generally qualitative, stating that results "compared well" and that there were "no significant differences."
| Acceptance Criteria | Reported Device Performance (TAS aPTT Controls) |
|---|---|
| Produce clotting times comparable to legally marketed predicate control device (Ci-trol; Dade) when used with TAS Analyzer and aPTT test cards. | "In clinical comparison studies the TAS aPTT Controls provided results that compared well with other legally marketed controls for the aPTT test (Ci-trol; Dade; Baxter Diagnostics, Inc.) when used to test the operation of the TAS Analyzer and test cards." |
| Clotting times must be within accepted, standard ranges. | "The controls produce clotting times which must be within accepted, standard ranges, to indicate that the analyzer and test cards are functioning properly and thereby help assure the accuracy of aPTT test results." (Implied to be met for adequate performance.) |
| Normal control produces a clotting time like that of a normal individual. | "The normal control produces a clotting time like that of a normal individual (but have different times for different reagent/instrument combinations)." |
| Abnormal control responds like a patient with a severe factor deficiency of the intrinsic coagulation pathway. | "Like other control manufacturers, we chose to make an abnormal control that responds like a patient that has a severe factor deficiency of the intrinsic coagulation pathway." |
| No significant differences in performance compared to the predicate device. | "There were no significant differences in the performance of the TAS aPTT Controls and the control from another manufacturer used as predicate device." (This is a summary statement of the comparison study's findings.) |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document mentions "clinical comparison studies" for the TAS aPTT Controls. However, the specific sample size for the test set is not provided. The data provenance (e.g., country of origin, retrospective or prospective) is also not explicitly stated. Given the context of a regulatory submission, it is highly likely these were prospective studies conducted in a clinical or laboratory setting.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This information is not applicable or not provided for this type of device and study. The "ground truth" for a coagulation control is its measured clotting time using a reference method or instrument, compared against established norms or predicate device performance, not typically requiring human expert consensus in the same way an AI diagnostic imaging system would.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This information is not applicable or not provided. Since the "ground truth" for this device involves objective measurements (clotting times) and comparison to a predicate device, an adjudication method for conflicting expert opinions would not be relevant.
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
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not mentioned or conducted as this device is an in vitro diagnostic control, not an AI/ML-assisted diagnostic tool that would involve human readers interpreting results.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
This question is not directly applicable in the context of this device. The TAS aPTT Controls are a reagent used with an analyzer and test cards. Their performance is inherently tied to the system they are controlling. The "standalone" performance, in this case, would refer to the performance of the control when used as intended, which is precisely what the comparison studies aimed to evaluate. There isn't an "algorithm only" component separate from the physical control and its interaction with the analyzer.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" for the TAS aPTT Controls is established by:
- Comparison to a legally marketed predicate device: The clotting times generated by the TAS aPTT Controls are compared to those generated by the Dade controls, which are already accepted as accurate.
- Established standard ranges: The clotting times are expected to fall within predetermined, accepted standard ranges for normal and abnormal controls, reflecting known physiological states (normal individual, severe factor deficiency).
- Functional testing: The device's ability to indicate that the associated analyzer and test cards are functioning properly, thereby assuring the accuracy of aPTT test results.
8. The sample size for the training set
Not applicable. This device is an in vitro diagnostic control, not an AI/ML system that requires a "training set" in the conventional sense. The "development" of the control involved designing formulations to mimic specific physiological states and then validating their performance against existing methods.
9. How the ground truth for the training set was established
Not applicable. As indicated in point 8, there is no "training set" in the AI/ML context for this device. The "ground truth" for the development of the controls would have been based on established clinical and laboratory standards for aPTT testing, characteristics of normal plasma, and plasma from patients with known coagulation factor deficiencies, along with the performance metrics of existing, validated control materials.
§ 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.