Many people don't know their blood type. Here's how to find out yours
There are four blood types, A, B, AB, and O. Your blood type is determined by the presence or absence of certain antigens.

CNN
Are you a blood type A, B or a combination of both?
What do you think? Many others are in the same boat. According to a CBS News poll, 62% of Americans knew their blood type.
These letters, with their pluses or minuses, can provide crucial information in an emergency situation. There are easy and accurate ways to find them.
According to Dr. Dayand Boge, the American Red Cross' Divisional Chief Medical Officer, most blood types are not compatible with only a few others.
Borge stated that accidental incompatible blood transfusions are rare but can prove to be deadly.
There are many easy ways to determine your blood type.
Ask your parents and doctor.
You should first check with your parents before you try any other methods. Your parents may have information or old records about your blood type. You may also contact your doctor to get this information.
Blood draw
Ask for your blood type next time you visit the lab to have your blood drawn. You can also call the lab if you have had blood drawn before to verify that they have this information. Visit your local clinic or healthcare provider to request a blood test.
Home blood test
Online ordering is also possible for an at-home blood test. It will be shipped directly to your home. The kit includes a needle and a card for you to draw blood. Results for many home tests take just minutes.
Blood donation
The blood is tested for blood type when you donate blood. Once you have donated blood to the Red Cross, you will be issued a blood donor card that will allow you to access your blood type for testing. This process takes only a few days and it is completely free. You may be able check your blood type if you have donated previously.
Saliva test
A saliva test, which isn't invasive and requires no blood draw, can be used to determine your blood type.
According to a study published by the Journal of Clinical & Diagnostic Research, about 80% of people secrete antigens in their saliva.
The test is therefore effective for most people, but not all. These tests are available online and can be purchased for a higher price than traditional at-home blood tests.