Blood Donor Eligibility Calculator

Blood donor screening protects both the person donating and the person receiving a transfusion. Collection services use a health questionnaire, identity and age checks, basic observations, a hemoglobin test, and rules about medical history and recent exposures. This calculator reviews only a small set of common starting criteria: age from 18 through 65 years, body weight of at least 50 kilograms, feeling well on the day, and a sex-specific hemoglobin threshold of 12.5 g/dL for women or 13.0 g/dL for men. Those values are useful for a preliminary check but are not universal. Some programs accept younger donors with parental consent, older established donors after assessment, or use different minimum weights and hemoglobin limits. Component type and collection volume can also change the requirement. The calculator therefore reports that a person meets basic criteria rather than declaring that the person is eligible. Final acceptance always belongs to the licensed collection service applying its current rules. The estimated blood volume shown with the result is a broad weight-based approximation: 65 mL per kilogram for women and 75 mL per kilogram for men. It provides context for why body size matters to collection safety, but it is not used here to prescribe a collection volume. Clinical estimates may use height, weight, sex, and body composition, and collection centers follow validated limits for the proportion of circulating volume that may be removed. Many factors not represented by the calculator can cause temporary deferral. Examples include fever or infection, pregnancy, recent childbirth, low iron, certain medicines, dental or surgical procedures, tattoos or piercings, vaccinations, travel to areas with transmissible infections, and a recent blood donation. Some medical conditions or exposure histories need individual review. Rules change as evidence, testing, and public-health circumstances evolve, so older advice may no longer apply. Answer the official questionnaire honestly and tell staff about symptoms, medicines, travel, procedures, and previous reactions. Eat normally, drink fluids, and follow the center's preparation instructions. If you feel unwell, have unexplained anemia, or are concerned about a medical condition, seek professional advice rather than donating to obtain testing. Even when this calculator shows that basic criteria are met, staff may defer a donation for safety, request documentation, or recommend a different component type or return date.