Tattoos and transfusion-transmitted disease risk: implications for the screening of blood donors in Brazil

Having a tattoo has been associated with serological evidence of hepatitis B and C viruses, as well as human immunodeficiency virus infections and syphilis; all of these are known to be transmissible by blood transfusion. These associations are of higher magnitude for individuals with nonprofessionally-applied tattoos and with two or more tattoos. Tattoos are common among drug addicts and prisoners, conditions that are also associated with transfusion-transmitted diseases. We examined the implications of these associations for the screening of blood donors in Brazil. Numbers of individuals who would be correctly or unnecessarily deferred from blood donation on the basis of the presence of tattoos, and on their number and type, were calculated for different prevalence situations based on published odds ratios. If having a tattoo was made a deferral criterion, cost savings (due to a reduced need for laboratory testing and subsequent follow-up) would accrue at the expense of the deferral of appropriate donors. Restricting deferral to more `at-risk' sub-groups of tattooed individuals would correctly defer less individuals and would also reduce the numbers of potential donors unnecessarily deferred. Key factors in balancing cost savings and unnecessary deferrals include the magnitude of the pool of blood donors in the population, the prevalence of individuals with tattoos and the `culture' of tattoos in the population. Tattoos can therefore be an efficient criterion for the screening of blood donors in certain settings, a finding that requires corroboration from larger population-based studies.