Blood Donation Eligibility Calculator

Blood donation eligibility in the US is set by the FDA (Food and Drug Administration) and applied by the American Red Cross, America’s Blood Centers and the hospital blood banks, with AABB (formerly the American Association of Blood Banks) writing the standards they work to. Other countries run their own rules, close to these but not identical. This calculator is a general pre-screening. Final eligibility is always decided by blood bank staff on the day.

Basic Requirements for Whole Blood Donation:

Common Temporary Deferrals:

• Tattoo: none in the US if it was done at a state-regulated shop with sterile needles and fresh ink; otherwise 3 months. The FDA cut this from 12 months in April 2020. The UK waits 4 months either way.
• Piercing: none if single-use equipment was used, otherwise 3 months.
• Travel to a malaria area: 3 months after you get back, for a visitor. Someone who lived in one waits longer.
• Cold or flu: until you feel well and have no fever. There is no fixed number of days.
• Antibiotics: until you have finished a course taken by mouth for an infection. Antibiotics for acne, or as a precaution before dental work, usually do not count.
• Surgery: no set wait. It depends on what the surgery was for, and you can usually give once you have healed and are back to normal activity. A blood transfusion during it means 3 months.
• Pregnancy: 6 weeks after delivery.
• Vaccination: no wait for most, including flu and COVID-19 vaccines. Live vaccines such as MMR (measles, mumps and rubella), chickenpox and yellow fever mean 2 to 4 weeks.

The form here asks about only a handful of these. The questionnaire at the centre covers medications, travel, sexual history and much more, and those questions exist to protect the patient who gets your blood.

Donation Types and Frequency:

Weight and Blood Volume:

Total blood volume runs at roughly 70 mL per kilogram of body weight, which works out at about one pint per 14 lbs of you. The 110 lb (50 kg) minimum exists so that a single pint stays a safe share of the total: at exactly the minimum weight, 470 mL out of about 3,500 mL is 13%. At 180 lb it is closer to 8%, which is why larger donors tolerate it more easily and why the floor is set where it is.

After Donation Tips:

Drink extra fluids for the next 24 to 48 hours and skip heavy lifting or hard exercise for a day. Eat iron-rich foods, and pair them with vitamin C, which meaningfully improves absorption of the iron in plants. Fluid volume is back within 24 hours, but red cells take 4 to 6 weeks and iron stores can take longer still. That gap is the whole reason for the 56-day interval.

One Donation Can Save Up to Three Lives:

Whole blood is separated into red cells, platelets and plasma, and each component can go to a different patient. Regular donors carry the supply, and demand never pauses.