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The new TAS HMT controls are intended to be used with the TAS Analyzer and HMT cards, previously cleared to market 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 the HMT test results. The controls are substantially equivalent in intended use to other controls used in coagulation assays.

The controls for TAS HMT 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 on a high dose of heparin. 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 qlass ampule containing Ivophilized 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 waste container, and a drcp of the plasma suspension is added to a TAS HMT 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 document describes the safety and effectiveness information for the TAS HMT Controls, which are in vitro coagulation controls intended for use with the TAS Analyzer and HMT cards to assure the proper functioning of the system.

Here's the breakdown of the acceptance criteria and the study that proves the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the TAS HMT controls are defined by the expected clotting time ranges and acceptable Coefficient of Variation (CV) for both normal and heparin controls, ensuring they indicate the system is functioning properly. The summary provides performance data from both non-clinical and clinical studies.

Interpretation: The reported performance data for both non-clinical and clinical studies consistently falls within or closely aligns with the established ranges and CVs, indicating that the device meets its implicit acceptance criteria for providing accurate and reliable control measurements. The stability and robustness under various conditions also demonstrate that the device performs as intended.

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Description:
  • Non-Clinical Performance Data: The summary mentions "Within day, day to day, operator, lot to lot, vial to vial, drop to drop variation studies," implying a comprehensive internal test set. However, specific numbers for samples, operators, lots, or vials are not provided.
  • Clinical Performance Data: Studies were performed at "two clinical study sites and at CDI." At each clinical site, the controls were tested in duplicate each day for 20 days. This means:
    • Site A: 2 controls (Normal & Heparin) * 2 replicates * 20 days = 80 measurements
    • Site B: 2 controls (Normal & Heparin) * 2 replicates * 20 days = 80 measurements
    • CDI: The testing at CDI also generated similar data, likely following the same duplicate daily for 20 days protocol, leading to another 80 measurements for similar consistency testing.
    • Total clinical measurements contributing to the reported means and CVs for variation would be at least 240.
• Data Provenance: The data is a mix of internal testing ("CDI") and external clinical sites. The specific country of origin is not explicitly stated, but CDI is located in Raleigh, NC, USA. The clinical study sites are referred to as "clinical study sites," suggesting these are real-world, prospective data collection points.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not applicable and not provided in the summary. The "ground truth" for this device, a coagulation control, is its expected clotting time measured against a reference standard or specified range. The performance is assessed by direct measurement against these pre-defined targets, not by expert interpretation of complex images or clinical outcomes.

4. Adjudication Method for the Test Set

This information is not applicable and not provided. As explained above, the assessment of a coagulation control involves direct measurement against established ranges, not subjective human interpretations requiring adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study was not done for the TAS HMT controls. This type of study is typically performed for diagnostic devices where human readers interpret medical images or data, and the goal is to evaluate if an AI system improves human performance. The TAS HMT controls are in vitro diagnostic reagents/controls, not an AI-powered diagnostic system requiring human interpretation.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, in essence, standalone performance was assessed. The TAS HMT controls themselves are not an "algorithm," but rather a reagent. The performance described here (clotting times, CVs, stability) is purely the performance of the control material in conjunction with the TAS Analyzer and HMT cards, essentially its "standalone" performance as an independent component of the system, without human interpretive input affecting the clotting time measurement itself. The human-in-the-loop primarily performs the physical steps of the test and interprets whether the numerical result falls within the acceptable range.

7. The Type of Ground Truth Used (Expert Consensus, Pathology, Outcomes Data, etc.)

The ground truth used for the TAS HMT controls is the expected clotting time range for a "normal" and a "heparin" control sample, derived from the physical-chemical properties of the control material designed to mimic these states. This is an analytical ground truth or defined reference range, not one established by expert consensus, pathology, or outcomes data in the way these terms are typically applied to more subjective diagnostic tests. The predicate device (ACT-trol controls) likely served as an initial benchmark for establishing these expected performance characteristics.

8. The Sample Size for the Training Set

This information is not provided and likely not applicable in the conventional sense for this type of device. The TAS HMT controls are chemical reagents, not a machine learning model that requires a distinct "training set." The development of the control formulation would involve extensive R&D and optimization, but this process doesn't align with the concept of a training set for an algorithm.

9. How the Ground Truth for the Training Set Was Established

This is not applicable as there is no "training set" in the context of an algorithm. The development of the TAS HMT controls involved:

• Designing formulations to mimic specific coagulation states (normal and heparinized).
• Using human plasma screened for antibodies and antigens.
• Selecting packaging for user-friendliness.
• Presumably, extensive internal R&D to characterize the clotting times and stability properties of various formulations until the desired performance characteristics were achieved, benchmarked against legally marketed controls (like ACT-trol).

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