Donating Blood

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Donating Blood

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What is blood donation?

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 through Canadian Blood Services or Héma Québec. Canadian Blood Services has over 40 permanent collection sites and thousands of mobile clinics.

About 450 mL (1 pint) of blood is taken when you donate. It takes about 15 minutes. The whole process—including answering questions and having a short examination—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.

Who can donate blood?

Most healthy people who are 17 to 71 years old can donate blood.

Some people can't donate because of health or other issues. For example, you may not be able to donate if:

  • Your hemoglobin levels are too low.
  • You are pregnant.
  • You have travelled to certain countries.
  • Your blood pressure is too high. Your blood pressure will be checked before you donate.
  • You take certain medicines.
  • You have certain health problems.
  • You weigh less than 50 kg (110 pounds).
  • You've recently been to the dentist. You should wait 24 hours after a cleaning or filling, and 72 hours if you've have dental surgery, a root canal, or a tooth pulled.
  • You have gotten a tattoo or have had body or ear piercing in the last 6 months.

Having a long-term illness, such as diabetes, doesn't mean you can't donate. You should call your nearest Canadian Blood Services and speak with someone on the medical staff if you'd like to donate. Those who are on insulin will not be able to donate blood.

Before you donate, you will fill out a Record of Donation form. The Record of Donation contains a confidential questionnaire that will help determine if you are eligible to give blood. You will also talk with a nurse who will ask you questions about whether you've done things that put you at risk for getting HIV or hepatitis.

What should you do BEFORE you give blood?

You can do a few things before you give blood to make sure that you have a good experience:

  • Make sure you feel good. Don't give blood if you feel ill.
  • Eat a good breakfast or lunch. But avoid fatty foods. They can affect some of the tests done on donated blood to make sure it's safe.
  • Drink plenty of fluids.
  • Get plenty of sleep the night before.

What happens when you donate blood?

You will fill out some forms and answer questions about your health.

A health professional will measure your hemoglobin, blood pressure, and temperature.

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.

What should you do AFTER you give blood?

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 light-headed.

In the hours after you give blood, make sure to:

  • Drink plenty of fluids to help replace the lost fluid.
  • Eat foods that have a lot of iron, such as lean red meat, raisins, and beans.
  • Limit your physical activity for several hours.

Most people feel fine after they give blood. But if you feel a little light-headed, lie down for a while. Drink plenty of fluids, and have some snacks. Call Canadian Blood Services 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.

What are the risks of donating blood?

There are no health risks in giving blood. You CANNOT get AIDS or other diseases 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.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Joseph O'Donnell, MD - Hematology, Oncology
Specialist Medical Reviewer Brian Leber, MDCM, FRCPC - Hematology
Last Revised May 27, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.