Knowing your blood type is important. I was recently filling out a volunteer application and was asked to provide my. Luckily, I knew off the top of my head that I’m type O-positive, but I wanted to find documentation to confirm that. I called my mom to see if blood type is listed on my birth certificate — no luck. I checked my physician’s health portal — also no luck.
So how does someone figure out their blood type if they don’t already know it?
If you have no clue what your type is, you’re not alone. According to a 2019 CBS News poll, only 66% of Americans reported knowing their blood type. Considering blood type can be vital to understanding your health, including your — and of course, saving you in an emergency — it’s important to know what kind of blood courses through your veins. Finding out your blood type is relatively simple. Here are three easy ways to find out your blood type.
Blood type basics
Blood type is categorized into one of these eight groups: A-positive, A-negative, B-positive, B-negative, O-positive, O-negative, AB-positive and AB-negative. But what determines blood type and what does that blood type mean?
Blood types are determined by antigens — a substance that triggers an immune response — on the surface of red blood cells. There are ABO antigens, which designate ABO blood types. This is determined by the ABO gene. For example:
- Type A blood type has the A antigen
- Type B blood type has the B antigen
- Type AB blood type has both the A and B antigen
- Type O doesn’t produce any A nor B antigen
There are also Rhesus (Rh) antigens, which determine if blood is “positive” or “negative.” If you have Rh proteins on the surface of your red blood cells, you are Rh positive. If you don’t have Rh proteins on the surface of your red blood cells, you have negative blood.
How can you type your blood?
Here’s three main ways to type your blood:
- Have your doctor do a blood test
- Donate blood
- Use an at-home blood test
1. Clinical test
One of the easiest and most effective ways to determine blood type is to have your doctor perform a test. A professional will draw blood and then perform two tests on the blood sample: forward typing and reverse typing.
During forward typing, the blood sample is mixed with antibodies against type A and B blood. Based on whether the blood cells stick together when mixed with the antibodies, your blood type can be determined from there. If your blood cells stick together when mixed with antibodies against type B blood, you have type B blood. If your blood cells stick together when mixed with antibodies against type A blood, you have type A blood.
To confirm the result, the next step is reverse typing, meaning the blood sample without red blood cells — called a serum — is mixed with type A and type B blood cells. Type A blood will have antibodies against Type B blood in the sample and type B blood will have antibodies against Type A blood. Type O blood will contain antibodies against Type A and Type B. So, if sticking occurs when the serum is mixed with type B blood cells, you have type A blood, and if sticking occurs when the serum is mixed with type A blood cells, you have type B blood.
I recommend calling your doctor’s office to see what a blood type test costs out-of-pocket and if it’s covered by insurance.
2. Donate blood
This is an easy — and free — way to determine blood type, but results are not immediate.
If you donate to a blood drive, you can simply ask the staff about your blood type. Blood usually is not tested right away, so it may take up to a few weeks to get results.
3. At-home blood test
At-home tests are relatively straightforward. You will usually start by wiping your finger with an alcohol wipe and then be…