An update on quality control for the PFA-100/PFA-200

Abstract

Testing of platelet function comprises a crucial element of hemostasis assessment, particularly for investigations into bleeding and/or bruising. The Platelet Function Analyzer (PFA)-100 is the most utilized primary hemostasis-screening test system available, as recently remodeled/upgraded to the PFA-200. Internal quality control (IQC) and external quality assessment (EQA) (including proficiency testing) represent critical elements of ensuring test practice quality. Although true for all tests, IQC and EQA are logistically challenging for platelet function testing, inclusive of the PFA-100/200. We accordingly update our experience with novel yet feasible approaches to both IQC and EQA of PFA-100/200. Over the past 10 years, a total of 43 challenges have been tested, with most challenges designed to mimic moderate or severe primary hemostasis defects. The current report is restricted to the last four years and has also differentially assessed PFA-100 vs. PFA-200 EQA results to identify potential variance. Numerical results for closure times (CTs) and participant-supplied interpretive comments were analyzed. Reported CTs for each challenge were within limits of expectation, and good reproducibility was evidenced by repeated challenges. Coefficients of variation (CVs) for challenges, generally ranging from 15% to 25%, were similar or better than those obtained using native whole blood and consistent with past reports. Participant interpretations were generally consistent with test data and expectations. There was no evident difference in PFA-100 vs. PFA-200 EQA test results. The EQA material has also been successfully evaluated from the perspective of potential IQC. To conclude, IQC and EQA processes for the PFA-100/200 have been established that are highly reproducible, supporting the concept of EQA/IQC for platelet function testing, and also facilitating monitoring and improvement in its performance. In terms of EQA, PFA-100 and PFA-200 instruments appear to behave similarly.

Keywords:

• EQA
• external quality assessment
• internal quality control
• IQC
• Platelet Function Analyzer
• PFA-100
• PFA-200
• proficiency testing

Acknowledgments

We thank present and past staff of the ICPMR laboratory, especially Soma Mohammed, Jane McDonald, Ella Grezchnik, Monica Ahuja, and Shabana Azimulla for ongoing technical support in PFA-100/200 testing. We also thank the present and past members of the RCPAQAP Haematology, for logistical support related to establishment and performance of the PFA-100/200 EQA testing module, and in particular John Sioufi and Katherine Marsden. NSW Health Pathology is acknowledged for providing in-kind support for the ICPMR laboratory. The views expressed in this report are those of the authors and not necessarily those of the RCPAQAP or NSW Health Pathology.

Declaration of Interest

The authors have no conflicts of interest to report.