# Measuring FVIII Activity and Thrombin Generation Simultaneously With a Novel Point of Care Platform (EnzySystem HemA): Qualitative Usability Evaluation

## TL;DR

A new point-of-care device called EnzySystem HemA was evaluated for usability in measuring blood clotting factors for hemophilia A patients.

## Contribution

The study introduces and evaluates a novel point-of-care platform for measuring FVIII activity and thrombin generation in hemophilia A.

## Key findings

- Five out of seven healthcare providers successfully performed the FVIII activity assay using the EnzySystem HemA.
- Participants found the platform acceptable despite usability issues, provided accuracy is proven.
- Thematic analysis revealed five key themes, including the platform's potential for faster results and patient engagement.

## Abstract

Hemophilia A is an inherited bleeding disorder with an increased risk of excessive bleeding. People affected by hemophilia A with a severe bleeding phenotype are treated prophylactically with hemostatic agents. Monitoring treatment and adjusting it to the individual patient’s needs is complicated by the scarcity of laboratories equipped to perform relevant coagulation assays and the absence of point-of-care testing platforms. A novel near-patient testing platform called the EnzySystem HemA aims to address this issue by measuring factor VIII (FVIII) activity and thrombin generation within 1 hour of 100 µL of whole blood.

This study assessed the usability of the EnzySystem HemA by health care professionals without prior training and gathered information on its perceived usability, effectiveness, usefulness, and acceptability.

A qualitative, single-center formative usability assessment was performed. Participants performed an FVIII activity assay with a mockup of the EnzySystem HemA and were interviewed about its acceptability, usability, effectiveness, and usefulness. Video recordings of the sessions were obtained with permission and subsequently reviewed to assess usability; thematic analysis was performed on the interview transcripts.

A total of 7 health care providers participated, all unaffiliated with the EnzySystem’s developer. Participants included 1 (14%) pediatric hematologist, 3 (43%; pediatric) nurses, and 3 (43%; pediatric) nurse practitioners. Two (29%) of the participants also held management positions. Five (71%) participants successfully performed the FVIII activity assay as intended. Of the remaining 2 participants, one applied insufficient force when inserting the blood tube, whereas the other was unable to transfer the blood into the EnzySystem. This latter step caused difficulties in 3 (60%) other participants; however, they completed it correctly. Five (71%) participants did not dispose of the EnzySystem components as intended, primarily due to compatibility issues of the disposable parts with the inlet of the US standard medical waste containers. Five themes were generated from the interviews: functional the way it is focuses on the acceptance of the prototype despite suggestions for various improvements, utility through faster results and increased access and potential for patient engagement relate to the envisioned benefits of the platform, and financial investment and return and ensuring accuracy reflect on potential barriers for implementation.

Despite significant usability issues, the need for faster and more accessible testing led participants to conclude that the current platform was acceptable for use, provided that proof of assay accuracy was demonstrated. The results of this study will form the basis for further development of the EnzySystem HemA. The effectiveness of any updates will be evaluated in future usability studies, which will also include people with hemophilia A as participants.