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Background and Objectives Individuals may donate blood in order to determine their infection status after exposure to an increased infection risk. Such test-seeking behaviour decreases transfusion safety. Instances of test seeking are difficult to substantiate as donors are unlikely to admit to such behaviour. However, manifestation in a population of repeat donors may be determined using statistical inference. Materials and Methods Test-seeking donors would be highly motivated to donate following infection risk, influencing the timing of their donation. Donation intervals within 2005-2014 of all Dutch blood donors who acquired syphilis ( N = 50), HIV ( N = 13), HTLV ( N = 4) or HCV ( N = 2) were compared to donation intervals of uninfected blood donors ( N = 7 327 836) using the Anderson-Darling test. We adjusted for length bias as well as for age, gender and donation type of the infected. Additionally, the power of the proposed method was investigated by simulation. Results Among the Dutch donors who acquired infection, we found only a non-significant overrepresentation of short donation intervals ( P = 0·54). However, we show by simulation that both relatively short and long donation intervals among infected donors can reveal test seeking. The power of the method is >90% if among 69 infected donors >35 (51%) are test seeking, or if among 320 infected donors >90 (30%) are test seeking. Conclusion We show how statistical analysis may be used to reveal the extent of test seeking in repeat blood donor populations. In the Dutch setting, indications for test-seeking behaviour were not statistically significant. This may, however, be due to the low number of infected individuals. [ABSTRACT FROM AUTHOR]

Background Rhesus D (RhD)-negative women pregnant with a RhD-positive child receive prophylactic injections to prevent haemolytic disease of the newborn. Because of the success of the prophylaxis, the number of naturally immunized women has decreased, thereby also decreasing the number of potential donors who provide the plasma from which the prophylaxis is made. As the current donor pool is ageing, the availability of the prophylaxis is threatened. Objectives Objectives are to investigate whether the anti-D population and the changes therein can be described by a relatively simple model, to determine the impact of ageing of the anti-D donors on the decline of the population and how many new donors should be recruited to meet future supply demand. Methods Data on Dutch anti-D donors in 1994-2013 were used to simulate the donor population size and age composition for various donor recruitment scenarios. Results With a continuous influx of 27 new donors per year and a donor stopping rate of 10% per year, the population size will stabilize at 195 donors, with 2·3% of donors stopping annually due to reaching the donor age limit. A formula is derived to estimate which donor recruitment and retention efforts are required to maintain a prespecified donor pool. Conclusion A relatively simple model can already describe and predict the size of the anti-D donor population and the impact of ageing accurately. [ABSTRACT FROM AUTHOR]