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The CoaguChek® Vantus System measures an INR (International Normalized Ratio) based on a prothrombin time (PT) response to monitor the effect of a therapy with vitamin K antagonists by using the CoaguChek XS PT test strips. The CoaguChek Vantus System uses fresh capillary whole blood from a finger stick.

The system is intended for properly selected and suitable trained users on the prescription of the treating doctor.

Users should be stabilized on anticoagulation with vitamin K antagonists for at least 6 weeks prior to single patient self-testing with the CoaguChek Vantus System.

The CoaguChek Vantus System is intended for single patient self-testing only for adults, age 22 years and older.

The CoaguChek Vantus consists of a handheld meter and associated test strips.

The CoaguChek Vantus meter is a small handheld instrument intended for the quantitative measurement of INR (International Normalized Ratio) based on a prothrombin time (PT) response, by using a single electrochemical test strip. It is designed for ease of use and is intended for patient self-testing only.

The CoaguChek XS PT Test strip contains a lyophilized reagent in dried form). The reactive components of this reagent consist of thromboplastin and a peptide substrate. When a sample is applied, thromboplastin activates coagulation, which leads to the formation of thrombin. At the same time, the meter starts to measure the time. The enzyme thrombin cleaves the peptide substrate, generating an electrochemical signal. Depending on the time elapsed when it first appears, this signal is then converted by means of an algorithm into customary coagulation units and the result is displayed.

The document describes the CoaguChek Vantus System, a device for measuring INR (International Normalized Ratio) based on prothrombin time (PT) response to monitor the effect of vitamin K antagonist therapy. It uses fresh capillary whole blood from a finger stick and is intended for single patient self-testing for adults aged 22 years and older, who have been stabilized on anticoagulation for at least 6 weeks.

1. A table of acceptance criteria and the reported device performance:

The document does not explicitly state "acceptance criteria" in a table format with pass/fail results for each criterion. However, it presents various performance study results for the CoaguChek Vantus System, comparing it against the predicate device (CoaguChek XS System) and a reference laboratory analyzer (Sysmex CA-1500). The implication is that meeting these performance benchmarks supports substantial equivalence.

Here's a summary of the reported device performance from various studies:

2. Sample sizes used for the test set and the data provenance:

• Repeatability Study: A total of 688 specimens from subjects on oral anticoagulation therapy and coagulation healthy subjects. There were 344 repeatability series performed at four Point-of-Care (PoC) sites. Data provenance is implied to be clinical samples collected for this study, likely in a prospective manner given the nature of repeatability testing. The document does not specify the country of origin.
• Reproducibility Study: Data was obtained from HCP measurements of three lots of CoaguChek XS PT controls covering four levels of controls, at all 4 PoC sites. The specific number of individual measurements is large (e.g., N=1040 for control levels 1 & 2, N=708/712 for control levels 3 & 4), indicating a substantial test set. Data provenance is implied to be clinical performance testing, likely prospective. Country of origin not specified.
• Method Comparison vs. Predicate: 207 samples were used, collected from both subjects not receiving anticoagulant and those on warfarin therapy. The study was conducted across 4 PoC sites. Data provenance is implied to be clinical samples, likely prospective. Country of origin not specified.
• Method Comparison vs. Reference System: 200 samples in total (67 from Site 1, 43 from Site 2, 47 from Site 3, 43 from Site 4). These were capillary whole blood samples measured on the CoaguChek Vantus System compared against venous plasma samples measured on the Sysmex CA 1500 laboratory analyzer. The study was performed across four (4) sites. Data provenance is implied to be clinical samples, likely prospective. Country of origin not specified.
• Expected Values / Reference Range Study: 121 healthy subjects were tested. Data provenance is implied to be clinical samples, likely prospective. Country of origin not specified.
• Endogenous and Exogenous Interferences: Not explicitly stated, but performed using "up to four CoaguChek XS PT Test strip lots, using fresh citrated venous whole blood from both normal and warfarin blood samples spiked separately with the interferents." The number of samples for each interferent is not detailed.
• Factor Sensitivity: Not explicitly stated in terms of sample size for human plasma, but states "Standard human plasma was mixed with varying amounts of factor II, V, VII or X deficient plasma to obtain plasma samples with different factor activities (0, 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 %)." For each test strip lot, "at least 4 measurements were performed per coagulation factor and dilution level." This suggests a controlled laboratory study.

The overall data provenance for the non-clinical and clinical performance evaluation sections points to controlled laboratory and point-of-care studies, suggesting a prospective data collection approach for the device validation.

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 device is an in-vitro diagnostic (IVD) device that measures a quantitative parameter (INR). The "ground truth" for such devices is typically established through reference methods and calibrated instruments, not through expert human review in the same way an imaging AI device's ground truth would be established.

• For Method Comparison studies: The ground truth was established by:
  • The predicate device (CoaguChek XS System), which is an already regulated and accepted device.
  • A reference laboratory analyzer (Sysmex CA-1500) using a specific reagent (Dade Innovin recombinant human tissue thromboplastin reagent). This laboratory method serves as the gold standard reference for PT/INR measurement.
• For other performance studies (Repeatability, Reproducibility, Linearity, Interference): The "ground truth" or reference is the precise and accurate measurement capabilities of the laboratory instruments and standardized clinical protocols.

Therefore, the concept of "experts" establish ground truth in this context typically refers to the expertise of the laboratory personnel performing the reference measurements and the established validity of the reference methods themselves, rather than a panel of diagnosticians reviewing cases. No specific number or qualifications of "experts" for reviewing individual data points are mentioned because the ground truth is analytically derived.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

Adjudication methods like "2+1" or "3+1" are typically used for qualitative or subjective assessments, such as in imaging studies where multiple readers interpret a finding and discrepancies are resolved by an adjudicator.

For this IVD device, the results are quantitative measurements (INR values). Therefore, there is no human "adjudication" of the test results in the sense of resolving differences in interpretation. The comparisons are statistical (e.g., Pearson r, slope, intercept from regression analysis, SD, CV). The "adjudication" is inherent in the statistical analysis and comparison to established reference methods.

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, an MRMC comparative effectiveness study was not conducted. This type of study is relevant for AI devices that assist human readers in tasks like image interpretation (e.g., radiology AI). The CoaguChek Vantus System is an in-vitro diagnostic device that provides a direct quantitative measurement (INR) for self-testing, not an AI system designed to assist human interpretation of complex data like medical images. Therefore, the concept of human readers "improving with AI assistance" does not apply to this device.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

Yes, the performance studies described in the document are effectively "standalone" performance evaluations of the device itself. The CoaguChek Vantus System is a standalone measurement device. It provides an INR result based on an electrochemical principle and internal algorithm. The human "in the loop" is the patient performing the finger stick and applying the blood, and the physician prescribing and managing the therapy. The device's measurement and output are not subject to real-time human interpretation or modification of the result before being displayed. The accuracy, precision, and interference studies directly assess the "algorithm only" performance (i.e., the instrument's ability to accurately measure and produce a result).

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

The ground truth for this device's performance evaluation was established using:

• Reference laboratory methods: Specifically, the Sysmex CA-1500 laboratory analyzer using Dade Innovin recombinant human tissue thromboplastin reagent was used as the reference method for PT/INR determinations in venous plasma samples. This is considered the analytical gold standard.
• Predicate device: The CoaguChek XS System (K062925) served as another comparison point, indicating substantial equivalence to an already marketed device.
• Standardized control materials and spiked samples: Used in precision, linearity, and interference studies to assess the device's accuracy and resistance to various factors.

This is a form of analytical ground truth derived from established, validated laboratory methods and reference materials, which is standard for IVD devices.

8. The sample size for the training set:

The document describes premarket notification (510(k)) and focuses on the performance studies (validation) rather than the development phase (training). The CoaguChek Vantus System utilizes an electrochemical detection principle and factory calibration rather than a machine learning model that would typically have a "training set." Therefore, the concept of a "training set" in the context of machine learning does not apply to this device as described.

9. How the ground truth for the training set was established:

As the device's operating principle is based on electrochemical measurements and factory calibration rather than a machine learning model, there isn't a "training set" with associated "ground truth" to be established in the sense of supervised learning. The calibration of each lot of test strips is "factory calibrated to a reference lot of human recombinant thromboplastin traceable to the World Health Organization International Reference Preparation," with this calibration information embedded in a code chip. This factory calibration is likely based on extensive internal studies and validated reference standards.

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