Pierre Toulon, Vice-chair of the World Federation of Hemophilia (WFH) Laboratory Sciences Committee, began the session by talking about the technical difficulties some laboratories face, such as sub-optimal use of control materials and use of stored calibration curves for factor assays. These difficulties are often explained by administrative issues or delays and shortages with the local reagent distributor. Toulon recommends that laboratories perform calibration curves using normal plasma pools in situations where commercial materials are limited.
Steve Kitchen, Director for UK NEQAS Blood Coagulation and lead clinical scientist at the Sheffield Haemophilia and Thrombosis Centre, presented the International External Quality Assessment Scheme (IEQAS) survey data from 2017 regarding testing in von Willebrand disease (VWD). “There is a huge problem of underdiagnosis in this disease,” said Kitchen.
“A change in the pattern of use of VWD assays has been observed and there are at least three latex particle-based assays available that are much more reliable, rapid and are being used more often in laboratory practice,” stated Kitchen.
Ian Jennings, Scientific Program Manager at UK NEQAS Blood Coagulation, talked about diagnostic challenges and inhibitor testing information generated by the WFH IEQAS Program Survey Data, including a factor VIII inhibitor exercise using a sample from a patient with severe congenital hemophilia. In this exercise, several laboratories came to erroneous diagnoses. Jennings stressed the need to use multiple assays to achieve a correct diagnosis.
Dianne Kitchen, IEQAS biomedical scientist, compared the participant questionnaire results. More cases of hemophilia A and B were diagnosed per year per centre between 2016 and 2017 compared with the period spanning 2010 to 2015. In contrast, rates of diagnoses of VWD did not change during these time periods.
Finally, Tim Woods, Manager and Deputy Director at UK NEQAS for Blood Coagulation, described operational and administrative issues for the WFH IEQAS. In particular, issues with temperature fluctuations during delivery of clotting factor concentrates around the world. Woods added that this issue has been addressed with the development of a small device that constantly tracks and reports the temperature inside a package of factor concentrates.