It is not possible to determine your blood type without a medical test. To find out your blood type, you can:

• Ask your doctor for a blood test.
• Donate blood; the blood donation center will typically test your blood type.
• Use an at-home blood type test kit, which can be purchased online or at some pharmacies.

Blood type is determined by the presence or absence of specific antigens on your red blood cells (A and B antigens) and the Rh factor (positive or negative). There are eight common blood types: A+, A-, B+, B-, AB+, AB-, O+, and O-.