There are several ways to find out your blood type, ranging from checking documents you already have to ordering a simple test online. The quickest option is looking at your birth certificate, which often lists blood type. If that doesn’t work, a lab test or at-home kit can give you a reliable answer for under $40.
Check Records You Already Have
Before spending any money, look through paperwork you might already have on hand. Your birth certificate is the most common place blood type gets recorded. If you don’t have a copy readily available, your state’s vital records office can issue one.
Other documents worth checking include military discharge papers (DD-214 for U.S. veterans), hospital discharge summaries from past surgeries or transfusions, and any records from past blood donations. If you’ve donated blood through the Red Cross or a local blood bank, your blood type was determined at that time and should be accessible through their records or online portal.
Your primary care doctor may also have your blood type on file, especially if you’ve had bloodwork done before surgery, during pregnancy, or as part of a transfusion. It’s worth calling their office and asking before scheduling a new test.
Order a Lab Test
If no existing records turn up your blood type, the most straightforward option is a standard blood typing test. Labcorp offers this test for $39 without insurance, and you can order it online without a doctor’s referral through their direct-to-consumer service. Quest Diagnostics offers a similar option at a comparable price. You’ll visit a local draw site, have a small blood sample taken, and typically get results within a few business days.
Doctors don’t usually order blood typing on its own unless there’s a medical reason. The standard situations that trigger the test include upcoming surgery, a blood transfusion, organ transplantation, or pregnancy. If you’re pregnant or planning to become pregnant, blood typing is part of your routine first-trimester lab panel, so you’ll find out automatically through prenatal care. Outside of those situations, ordering the test yourself through a lab’s consumer portal is often the simplest route.
Use an At-Home Kit
At-home blood typing kits let you determine your type with a finger prick in about five minutes. The most widely available option is the Eldoncard, an FDA-cleared card that’s been on the market since 1979. It contains dried antibodies in separate circles on the card. You place a drop of blood on each circle, add water, and watch for clumping. If your blood cells clump in a particular circle, it means your red blood cells carry the corresponding marker.
These kits are accurate. In clinical testing, the Eldoncard matched conventional lab results with 100% sensitivity and specificity in one study, and 99.5% agreement in another that tested 200 samples. They’re available online for roughly $10 to $15. The main limitation is user error: if you don’t follow the instructions carefully or use too little blood, results can be unclear. When in doubt, a lab test is the more reliable backup.
Donate Blood
If you’re eligible to donate, this is a free way to learn your blood type while doing something useful. Blood banks type every donation, and most organizations will notify you of your blood type afterward. The Red Cross, for example, makes your blood type available through their donor app or online account after your first donation.
How Blood Typing Works
A blood type test identifies two things: your ABO group and your Rh factor. Together, these give you one of eight common blood types.
For the ABO portion, a lab mixes your blood sample with antibodies that react against type A and type B blood. If the cells clump together when exposed to anti-A antibodies, you’re type A. If they clump with anti-B, you’re type B. Clumping with both means AB, and no clumping at all means type O. Rh testing works the same way: your sample is mixed with antibodies that detect the Rh protein on red blood cells. If clumping occurs, you’re Rh positive. If not, you’re Rh negative.
The result is a two-part label like O+ or AB-. The letter is your ABO group, and the plus or minus is your Rh status.
Blood Type Distribution in the U.S.
Knowing what’s common can give you context for your result. O positive is the most common blood type in the U.S., found in about 38% of the population. A positive comes next at roughly 1 in 3 people. The rarest types are AB negative (less than 1%) and B negative (less than 2%).
- O+: 38%
- A+: ~33%
- B+: ~9%
- O-: 7%
- A-: ~6%
- AB+: less than 4%
- B-: less than 2%
- AB-: less than 1%
Why Your Blood Type Matters
For day-to-day life, your blood type rarely comes up. But in emergencies, it becomes critical. If you need a blood transfusion, receiving the wrong type can trigger a dangerous immune reaction. Hospitals will always type your blood before a planned transfusion, but knowing your type ahead of time can speed things up in urgent situations.
During pregnancy, Rh factor is especially important. If you’re Rh negative and your baby is Rh positive, your immune system can develop antibodies that attack the baby’s red blood cells. This is called Rh incompatibility, and it’s screened for during the first trimester. If the mismatch is detected, you’ll receive medication during pregnancy to prevent complications. This is one of the main reasons blood typing is built into routine prenatal care.