Factor VIII/IX inhibitor testing practices in the United Kingdom: Results of a UKHCDO and UKNEQAS national survey

International Council for Standardization in Haematology recommendations for laboratory measurement of factor VIII and FIX type I inhibitors

This guidance document has been prepared on behalf of the International Council for Standardisation in Hematology. The aim of the document is to provide guidance and recommendations on the measurement of factor VIII (FVIII) and factor IX (FIX) inhibitors. After an introduction on the clinical background and relevance of factor VIII and factor IX inhibitor testing, the following aspects of laboratory testing are included: screening for inhibitors, assay principle, sample requirements, testing requirements and interpretation, quality assurance, interferences and recent developments. This guidance document focusses on recommendations for a standardised procedure for the laboratory measurement of FVIII and FIX type I inhibitors. The recommendations are based on published data in peer-reviewed literature and expert opinion.

Advantages of external quality assessment-EQA programs

INTRODUCTION

The first external quality assessment (EQA) in Thrombosis and Haemostasis was elaborated over 20 years ago, and since then, several national and international EQA institutions have been established.

AIM

Display the benefits of EQA programs.

METHODS

The spectrum of EQA action was evaluated ranges from improving the performance of the local laboratory to highlighting inadequate diagnostic tests that need to be replaced by new technologies.

RESULTS

The first result approach is related to a national management of quality in laboratories. In recent years, Brazil has invested in an EQA program to aid public policy in the laboratory area. During this period, a group of haemostasis laboratory specialists were invited to manage the results and help the Ministry of Health with applying these results as a strategy to improve laboratories. Thus, in collaboration with NEQAS-BC, the University of Campinas - UNICAMP, established a Brazilian EQA program for Blood Coagulation. The second result approach is related to FVIII inhibitor assay performance evaluation, which is another type of EQA program benefit. Despite the assay being considered the gold standard to measure neutralised immunoglobulins for FVIII since 1975, over 40 years ago, the test still has a high coefficient of variation. Results from NEQAS-BC and WFH IEQAS program demonstrate the inter-laboratory variation across the United Kingdom over the last years and among emergent countries.

CONCLUSION

The EQA programs have an important educational role in helping countries manage their public policy and in the international inquiry regarding the necessity of new technologies in haemostasis.