The fastest way to find your blood type is to check existing medical records, but if it’s not there, you can get tested at a lab for around $50, use an at-home kit for under $10, or learn it for free by donating blood. Each method has different tradeoffs in speed, cost, and reliability.
Check Your Medical Records First
If you’ve ever had surgery, received a blood transfusion, donated blood, or been pregnant, your blood type was almost certainly tested. Hospitals routinely type blood before any surgical procedure, before transfusions, and during prenatal care. These results live in your medical records, and most health systems let you access them through an online patient portal. Look for laboratory results labeled “ABO group” or “blood type.”
A common misconception is that your blood type appears on your birth certificate. Standard U.S. birth certificates do not include blood type. Hospitals only test a newborn’s blood in specific circumstances, such as when the mother is Rh-negative, and even then the result may not be stored in a place you can easily find years later. Newborn blood typing is also less straightforward than adult testing because babies don’t produce their own blood type antibodies until 3 to 6 months of age, which can make certain testing methods unreliable.
If you can’t find results online, call your doctor’s office or the hospital where you had a procedure and ask specifically for your blood bank or lab records.
Donate Blood and Get Typed for Free
Blood donation centers type every unit of donated blood, and they’ll share your results with you afterward. Organizations like the American Red Cross include your blood type in your donor profile, which you can access online or through their app after your first donation. This is the only method that costs nothing and uses the same professional lab-grade testing that hospitals rely on. The tradeoff is time: you’ll need to wait days or weeks for your donor card or profile to update with results.
Order a Lab Test Directly
If you want a professional result without donating blood, you can order a blood typing test through a commercial lab. Quest Diagnostics, for example, charges about $52 for ABO typing and another $52 for Rh typing. Some labs bundle both into a single order. You can often purchase these tests online without a doctor’s referral, then visit a local draw site for a quick blood sample.
In a clinical lab, ABO and Rh typing takes roughly 45 minutes once the sample arrives. Results are typically available within one to two business days through the lab’s patient portal. Insurance generally won’t cover blood typing done out of curiosity since it needs to be tied to a medical reason like pregnancy or an upcoming procedure. If your doctor orders it as part of prenatal care or surgical planning, it’s usually covered.
Use an At-Home Blood Typing Kit
Home blood typing kits like the EldonCard let you determine your ABO group and Rh status using a finger prick. You place drops of blood onto a card pretreated with antibodies, and the pattern of clumping tells you your type. Results appear in minutes.
These kits are surprisingly accurate when used correctly. A large multicenter study found that the EldonCard achieved a 99.9% concordance rate with standard laboratory methods for ABO and Rh typing. Other validation studies have reported 100% agreement. The kits typically cost $8 to $15 and are available from online retailers and some pharmacies.
The main limitation is user error. If you don’t apply enough blood, don’t mix properly, or misread the clumping pattern, you can get a wrong result. Home kit results are also not accepted for medical purposes. No hospital will use your EldonCard result to guide a transfusion. But for personal knowledge, they’re a reliable and inexpensive option.
What Your Results Mean
Blood typing identifies two things: your ABO group (A, B, AB, or O) and your Rh factor (positive or negative). That gives you one of eight common types. Type O-positive is the most common in the U.S., while AB-negative is the least common among standard types.
Your ABO group is determined by specific molecules, called antigens, on the surface of your red blood cells. Type A blood has A antigens, type B has B antigens, AB has both, and O has neither. Your Rh factor depends on whether you carry a particular protein called the D antigen. If you have it, you’re Rh-positive. If not, Rh-negative.
Beyond these eight types, there are hundreds of other blood group systems. In extremely rare cases, people lack all Rh antigens entirely. This condition, sometimes called “golden blood” or Rh-null, has been reported in only about 43 people worldwide. People with Rh-null blood face serious challenges if they ever need a transfusion, since only blood from another Rh-null donor is fully compatible. They’re often encouraged to bank their own blood in advance of any planned surgery.
Why Knowing Your Type Matters
In everyday life, knowing your blood type is mostly useful background knowledge. It becomes critical in emergencies. When hospitals don’t know a patient’s blood type during a trauma, they default to type O red blood cells because O is compatible with all other types. Rh-negative blood is reserved for women of childbearing age and children, while Rh-positive units go to adult males. Once the patient’s actual type is identified (which takes about 45 minutes), the hospital switches to type-specific blood.
Rh factor is particularly important during pregnancy. If you’re Rh-negative and your baby is Rh-positive, your immune system can develop antibodies against the baby’s blood cells. This is preventable with treatment, but only if your Rh status is known. This is why blood typing is standard in prenatal care.
Knowing your type also speeds things up if you ever need a transfusion for a planned surgery. While the hospital will always confirm your type independently, having it on file can help streamline the process.