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The microINR System measures prothrombin time (PT) expressed in International Normalized Ratio (INR), for monitoring oral anticoagulant therapy with warfarin.

The microlNR System consists of a meter and chips (test strips) and uses fresh capillary whole blood from a fingerstick. The microlNR System is intended for patient self-testing use as well as for healthcare professionals at Point of Care settings.

The microlNR System is intended for use in patients 18 years old or older. Patients must be stable on warfarin medication for at least 6 weeks before starting to use the microINR System.

For Self-testing use: The System is intended for properly trained users under specific prescription of a physician. Caution: The microINR System is not in patients who are transitioning from heparin treatment to VKA therapy. The microINR System is not intended to be used for screening purposes.

The modified device microINR System containing the microINR Expert Meter is derived from the existing devices microINR Meter and microINR Link Meter. The change is for the incorporation of additional connectivity functions (Wi-Fi and Ethernet connectivity on top of the Bluetooth connectivity of the microINR Link), a touchscreen, a barcode scanner as well as other configurable settings and optional functions (such as the option of including operator and patient identification). All the actions related to the extra functionalities and configurable settings are set before or after performing the analytical test. The fundamental scientific technology of the modified device and its performance has not changed. No performance changes to the microINR System have been implemented since its initial clearance on K180780 and its home use clearance in K201185.

The provided text is a 510(k) summary for the microINR System, specifically addressing changes made to the device (the incorporation of the microINR Expert Meter). The key takeaway from the document is that the fundamental scientific technology and performance of the device have NOT changed. The modifications primarily involve connectivity, user interface, and optional features.

Therefore, the document does not present new performance data based on a new study for the microINR System's core functionality (measuring PT/INR). Instead, it relies on the performance previously cleared under K180780, K201185, and K231711. The testing described in section 7 ("Testing on the modified device was conducted as follows: Software verification and validation; testing for Radiofrequency, Electromagnetic Compatibility and Electrical Safety: Cybersecurity analysis and testing; and Usability testing.") relates to the new functionalities added to the expert meter, not the core PT/INR measurement.

Given this, I cannot extract numerical "acceptance criteria" and "reported device performance" directly from this document for the PT/INR measurement. The document states:

• "No performance changes to the microINR System have been implemented since its initial clearance on K180780 and its home use clearance in K201185."
• "The fundamental scientific technology of the modified device and its performance has not changed."
• "The performance characteristics of the microINR System remain the same."

Therefore, for the purpose of answering your request based solely on the provided text, the answer will reflect that the core performance information is not detailed here, as the submission focuses on documenting that the new components do not negatively impact the already cleared performance.

Here's the information based on the provided text, with explicit notes where information is not available or where the focus is on the new functionalities rather than the core PT/INR measurement:

Acceptance Criteria and Device Performance for microINR System (Focus on New Expert Meter Functionalities)

The provided 510(k) summary for the microINR System (K243543) primarily addresses changes related to the incorporation of the "microINR Expert Meter," which introduces additional connectivity, a touchscreen, barcode scanner, and other configurable settings. The document explicitly states that the fundamental scientific technology and the performance of the device related to its intended use (measuring Prothrombin Time/INR) have not changed from previous clearances (K180780, K201185, K231711).

Therefore, the "study" described in the document primarily focuses on verifying and validating these new functionalities to ensure they do not introduce new questions of safety or effectiveness, rather than re-evaluating the core PT/INR measurement accuracy.

1. Table of Acceptance Criteria and Reported Device Performance

As the core performance of the PT/INR measurement is stated to be unchanged and reliant on previous clearances, a specific table of numerical acceptance criteria and reported new performance for PT/INR is not present in this document. The testing detailed pertains to the new functionalities of the Expert Meter. The acceptance criteria for these new functionalities are broadly stated as:

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

The document does not specify quantified sample sizes for the testing of the new functionalities. It generally refers to "Software verification and validation; testing for Radiofrequency, Electromagnetic Compatibility and Electrical Safety: Cybersecurity analysis and testing; and Usability testing."

Data provenance (e.g., country of origin, retrospective/prospective) for these specific verification and validation activities is not detailed.

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

Given that the document focuses on technical verification (software, electrical, cybersecurity) and usability of new features (connectivity, touchscreen, barcode scanner), and not the diagnostic accuracy of PT/INR measurement, the concept of "experts establishing ground truth" in the clinical sense (e.g., radiologists for imaging) is not directly applicable here. The ground truth for these tests would be technical specifications and user expectations. The document does not specify the number or qualifications of personnel involved in these specific verification and validation activities.

4. Adjudication Method for the Test Set

Not applicable in the context of the described technical verification and validation of new functionalities. Adjudication methods like 2+1 or 3+1 are typical for clinical outcome or diagnostic accuracy studies involving human interpretation, which is not the focus of the testing described for this device's modifications.

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

No MRMC study was done or described in this document. This type of study is relevant for AI-assisted diagnostic tools where human reader performance is being evaluated, which is not the nature of the microINR System or the modifications herein.

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

The microINR System is a point-of-care device that requires human interaction (fingerstick, applying blood, reading results). Therefore, a purely "standalone" (algorithm only) performance is not a direct concept for this type of device. The document states that the "fundamental scientific technology... has not changed," implying that the core measurement algorithm's performance remains as previously cleared. The current submission focuses on added functionalities (connectivity, display) to an already cleared system.

7. The Type of Ground Truth Used

For the new functionalities tested: The ground truth would be based on engineering specifications, software requirements, cybersecurity standards, and usability design principles. The document does not specify the exact methods or "ground truth" for each of these technical tests, only that they met pre-determined acceptance criteria.

For the core PT/INR measurement: This information would reside in the previous 510(k) submissions (K180780, K201185, K231711). Typically, ground truth for INR devices is established against a reference laboratory method (e.g., plasma-based PT/INR using a validated coagulometer).

8. The Sample Size for the Training Set

The document does not describe a "training set" in the context of machine learning model development. This device is an in-vitro diagnostic (IVD) device, not an AI/ML diagnostic tool that requires a training set for model development in the same way. The core measurement algorithm's development (if it had a "training" phase) would have occurred prior to the initial clearances.

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

Not applicable as this is not an AI/ML device that uses a "training set" in the described context.

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The microlNR System measures prothrombin time (PT) expressed in International Normalized Ratio (INR), for monitoring oral anticoagulant therapy with warfarin.

The microINR System consists of a microINR Meter and microINR Chip and uses fresh capillary whole blood from a fingerstick.

The microINR System is intended for patient self-testing use as well as for healthcare professionals at Point of Care settings.

The microlNR System is intended for use in patients 18 years old or older. Patients must be stable on warfarin medication for at least 6 weeks before starting to use the microINR System.

For Self-testing use: The System is intended for properly trained users under specific prescription of a physician. Caution: The microINR System is not in patients who are transitioning from heparin treatment to VKA therapy. The microINR System is not intended to be used for screening purposes.

The microINR® System is comprised of a portable measuring device (microINR® Meter) and test strips (microINR® Chips) in which the capillary blood sample flows through capillary action.

The microINR® Chip contains a reagent in dried form which consists of thromboplastin, and contains two symmetrical regions, the measuring channel and a control channel. The microINR® Meter measures International Normalized Ratio (INR) based on a Prothrombin Time (PT) assay carried out in the microINR® Chip based on microfluidic technology with machine vision detection.

The microINR® System has a multi-level On-board Quality Control. Multiple key functions and elements of the system are checked and if deviations are detected, error messages are displayed and test results are not reported.

Here's a summary of the acceptance criteria and study detailed in the provided document for the microINR System:

1. Table of Acceptance Criteria and Reported Device Performance

The FDA 510(k) summary does not explicitly list "acceptance criteria" for the self-testing use case in a table format with pass/fail thresholds. Instead, it describes clinical studies and their outcomes designed to demonstrate that the device performs equivalently for patient self-testers as for healthcare professionals, particularly in terms of accuracy and precision. The success of the study itself serves as the demonstration of meeting the required performance for the new intended use.

Here's a breakdown of the key performance metrics reported, framed against the implicit acceptance criterion of equivalence to healthcare professional (HCP) results and a laboratory reference:

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

• Accuracy (PST vs. HCP): N = 225 patients. The study was conducted at "four clinical sites" and involved patients self-testing in a "home setting for up to 2 weeks" with "2 scheduled visits to their study site." This indicates a prospective study design. The country of origin of the data is not specified.
• Accuracy (PST vs. Laboratory System): N = 112 patients. Data collected at the second visit by PSTs was compared to a laboratory system. As part of the same study as above, this is also prospective, and the country of origin is not specified.
• Precision (PST): N = 110 patients (paired results). Data collected by patient self-testers at the second visit to the clinical sites. This is also prospective, and the country of origin is not specified.

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

For the ground truth comparison:

• Healthcare Professionals (HCPs): The study compares patient self-tester results to "healthcare professionals using the microINR® System." While the exact number of HCPs is not stated, it implies multiple professionals across the four clinical sites. Their specific qualifications (e.g., radiologist with 10 years of experience) are not provided, beyond being "healthcare professionals."
• Laboratory System: The "ACL TOP 500" is cited as the reference laboratory system. This is an automated coagulation analyzer, implying the ground truth was established by a validated laboratory method rather than individual expert consensus.

4. Adjudication Method for the Test Set

The document does not describe an explicit adjudication method (like 2+1 or 3+1) for resolving discrepancies in the test set. Instead, it's a direct comparison of the microINR results from patient self-testers against the microINR results from healthcare professionals and against a reference laboratory system.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

This is not applicable. The microINR System is a diagnostic medical device for measuring prothrombin time (PT) expressed as INR, not an AI-assisted diagnostic tool for interpretation by human readers. Therefore, an MRMC comparative effectiveness study where human readers improve with AI assistance is not relevant to this device.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, in a way. The device itself, the microINR System, is the "standalone algorithm" that measures INR. The studies evaluate its performance (accuracy, precision) in the hands of two different user groups (patient self-testers and healthcare professionals) and against a laboratory reference, effectively assessing its standalone performance for each user group.

7. The Type of Ground Truth Used

The ground truth used for the clinical studies was a combination of:

• Clinical Reference (HCP results): INR results obtained by trained healthcare professionals using the microINR System. This serves as a "human expert" benchmark for the device's performance when operated by trained professionals.
• Laboratory Reference Method: INR results obtained from a standard "laboratory system (ACL TOP 500)." This is an established independent gold standard for PT/INR measurement.

8. The Sample Size for the Training Set

The document does not explicitly state a "training set" sample size for the new intended use (patient self-testing). The microINR System was previously cleared, meaning its core algorithm for INR measurement was already established. The studies for this 510(k) are focused on validating its performance in the hands of self-testers, rather than "training" a new algorithm. The document mentions that "following training, the patients self-tested." This implies the patients themselves received training on how to use the device, not that their data was used to train the device's internal algorithm.

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

Given that this 510(k) primarily addresses a new user population for an already cleared device, there isn't a "training set" in the sense of machine learning algorithm development. The core measurement principle and validation were established under the previous clearance (K180780), which would have involved its own validation studies against established reference methods. For the current submission, the focus is on demonstrating that trained patients can achieve equivalent results, with ground truth established as described in point 7.

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