Prevalence and causes of blood donor deferrals among clients presenting for blood donation in northern Tanzania.

Introduction: Blood is an important requirement in different medical and surgical conditions with half of all donations are from developing countries. Lack of eligibility among blood donors who present for blood transfusion, called blood donor deferral is associated with the unsustainable and inadequate amount of blood collected by blood banks worldwide. However, the prevalence and causes of blood donor deferrals are not well known in Tanzania where less than one-third of actual needs of blood is collected, leading to unmet demand of blood for transfusion, and causing unwanted morbidity and mortality.