Skip to Content
Home > Health Information > Health Library > Donating Blood
Blood donation is giving some of your blood so that it can be used to help someone else. Donated blood helps people who have lost blood in an accident or who have an illness such as cancer, anemia, sickle cell disease, or hemophilia.
Donated blood includes red blood cells and the other things that make up the blood, such as platelets and plasma. Blood that contains all the parts is called whole blood.
You can donate blood at American Red Cross clinics or other clinics or blood banks. You may be able to donate during blood drives at your workplace.
About 1 pint (480 mL) of blood is taken when you donate. It takes about 10 minutes. The whole process—including answering questions and having a short exam—takes up to an hour.
Donated blood is tested to make sure that it is safe to use. It's also checked for its type. This makes sure that the person who needs blood gets the right type.
To donate blood, you must:
Some people can't donate because of health or other issues. For example, you may not be able to donate if:
Having a long-term illness, such as diabetes, doesn't mean you can't donate. You may be able to give blood if your health problem is under control. But you shouldn't donate blood if you feel like you're getting a cold or the flu.
Before you donate, a health professional will ask about your current and past health to make sure that you can donate. Some of these questions are very personal, so you will be asked them in private. You will be asked these questions every time you give blood, because the list of who can give blood may change, or your health may change.
You can do a few things before you give blood to make sure that you have a good experience:
You will fill out some forms and answer questions about your health.
A health professional will measure your temperature, pulse, and blood pressure. He or she also will use a finger-stick test to make sure that you have enough iron in your blood.
The health professional will clean the arm you will use to give blood. Then he or she will put a needle into a vein on the inside of your elbow. The needle is attached to a bag to collect the blood. You will probably feel a quick pinch when the needle goes in.
You may be given a soft ball or another object to squeeze every few seconds to help the blood flow.
When the bag is full, the health professional will take out the needle. He or she will wrap a bandage around your arm to stop any bleeding.
Right after giving blood, you'll be asked to sit for a while and have some water or juice and a snack.
When you leave, get up slowly to make sure that you're not lightheaded.
In the hours after you give blood, make sure to:
Most people feel fine after they give blood. But if you feel a little lightheaded, lie down for a while. Drink plenty of fluids, and have some snacks. Call the blood bank or clinic if you feel sick within 24 hours after giving blood.
Your body will replace the lost fluid in 24 hours. (It takes a few weeks to replace red blood cells.) You will have to wait 56 days before you can give whole blood again.
There are no health risks in giving blood. You CANNOT get HIV from donating blood. The needle and bag used to collect blood are sterile and prepackaged. A new package is used every time.
You may have a small bruise on your arm. In rare cases, a person's arm may bleed after the bandage is taken off. If this happens, raise your arm and put pressure on the needle site for several minutes.
Some people feel faint after they donate blood. This is more common for younger people and for people who are donating for the first time. If you have fainted after donating blood and you choose to donate again, be sure to tell the person who is going to draw your blood. Drinking extra water before you donate may reduce this risk.
After donation, your blood is tested for certain diseases, such as hepatitis B and C, HIV, West Nile virus, and HTLV-I/II viruses. Donated blood must pass all of these tests. If any disease is detected, the blood is thrown away and the donor is notified. The blood is tracked so it can be traced back to the donor and the collection location.
Other Works Consulted
McCullough J (2010). Blood procurement and screening. In K Kaushanksy et al., eds., Williams Hematology, 8th ed., pp. 2279–2286. New York: McGraw-Hill.
Current as ofMay 6, 2018
Author: Healthwise StaffMedical Review: E. Gregory Thompson, MD - Internal MedicineAdam Husney, MD - Family MedicineMartin J. Gabica, MD - Family MedicineBrian Leber, MDCM, FRCPC - Hematology
Current as of:
May 6, 2018
Medical Review:E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Brian Leber, MDCM, FRCPC - Hematology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2018 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.
You'll find Decision Points to help you answer questions about:
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
See important information from Billings Clinic on Non-discrimination and Interpreter Services.
Billings Clinic is proud to be an equal opportunity/affirmative action (EOE/AA) e-verify employer.