False‐reactive microbiologic screening test results in Swedish blood donors—how big is the problem? A survey among blood centers and deferred donors

BACKGROUND: Screening of blood donors for markers of transfusion‐transmissible infectious agents leads to a varying number of false‐reactive test results and sometimes thereby temporary or permanent deferral of donors and also to loss of collected units. STUDY DESIGN AND METHODS: Data on false‐reactive screening test results in 2002 and 2003 were collected from 19 blood centers in Sweden. A questionnaire was sent to donors deferred because of false‐reactive screening test results to investigate their perception of the information and their reaction to the deferral. RESULTS: Testing of 21,189 samples from new donors and 423,543 donations from regular and/or repeat donors produced 1,059 false‐reactive test results, mostly from hepatitis C virus antibody testing, and 299 deferrals. Six different human immunodeficiency virus tests led to between 0.02 and 0.2 percent false‐reactive results. The deferral rate varied considerably between different counties. Of 204 deferred donors contacted, 180 (88%) answered the questionnaire. More than 80 percent were worried about their test results and worry was more common among those who did not feel sufficiently informed. CONCLUSION: The results imply that there is a need for a more standardized approach to the screening of blood donors and donations with the aim of minimizing the number of false‐reactive screening test results. They also emphasize the importance of appropriate information and support to deferred donors.