Not knowing your blood type is more common than you might think, surveys suggest that nearly 50% of people don’t know their blood type. But whether you’re preparing for a medical procedure, planning to donate blood, or simply curious about your health, knowing how to find your blood type is genuinely important information.
In this guide, we’ll walk you through six reliable methods to find out your blood type, including options that are completely free, others you can do from home, and the fastest approach if you need an answer today. By the end, you’ll know exactly which method fits your situation best.
Understanding Blood Types: The Basics
Before diving into how to find your blood type, it helps to understand what blood typing actually means. Your blood type is determined by the presence or absence of certain antigens (proteins) on the surface of your red blood cells.
There are two major classification systems used in medicine:
The ABO Blood Group System
The ABO system divides blood into four main types based on which antigens are present:
- Type A: has A antigens on red blood cells and B antibodies in plasma
- Type B: has B antigens on red blood cells and A antibodies in plasma
- Type AB: has both A and B antigens, no A or B antibodies (universal recipient)
- Type O: has no A or B antigens, but has both A and B antibodies (universal donor)
Type O is the most common blood type globally, found in about 44% of the population. Type AB is the rarest, occurring in only about 4% of people.
The Rh Factor
On top of the ABO type, your blood is also classified as either Rh-positive (+) or Rh-negative (−), based on whether you have a specific protein called the Rh factor on your red blood cells.
This gives us the eight blood types most people are familiar with: A+, A−, B+, B−, AB+, AB−, O+, and O−. About 85% of the population is Rh-positive.
The Rh factor is especially important during pregnancy. If an Rh-negative mother carries an Rh-positive baby, it can lead to a condition called Rh incompatibility, which doctors monitor and manage carefully.
Why Knowing Your Blood Type Matters
You might wonder: does it really matter if you know your blood type? The answer is yes, and here’s why.
Medical Emergencies
In trauma situations or emergencies requiring a transfusion, time is critical. While hospitals will always test your blood before a transfusion, knowing your type in advance can help medical staff make faster decisions. In cases where there’s no time to test, universal donor blood (O−) is used, but knowing your type gives doctors more options.
Pregnancy Planning
As mentioned above, Rh incompatibility between a mother and baby can cause serious complications, including hemolytic disease of the newborn. If you’re pregnant or planning to become pregnant, knowing your blood type and Rh factor is something your OB-GYN will want to know early.
Blood Donation
Certain blood types are always in high demand. O-negative blood is the universal donor type used in emergency situations when there’s no time to match blood types. If you’re O−, knowing your blood type may inspire you to donate more regularly, your blood literally saves lives in emergencies.
Organ Transplants
Blood type compatibility is one of the key factors in matching organ donors to recipients. Whether you’re on a transplant waiting list or registered as an organ donor, your blood type is part of your medical profile.
Personal Curiosity and Health Awareness
Some research suggests associations between blood type and certain health risks, including heart disease, certain cancers, and susceptibility to infections. While the science is still developing, knowing your blood type is part of having a complete picture of your health.
Method 1: Check Your Medical Records or Patient Portal
The easiest place to start is your existing medical records. If you’ve ever had bloodwork done, during a hospital visit, routine physical, surgery, pregnancy, or a blood disorder screening, your blood type may already be on file.
How to Access Your Medical Records Online
Most healthcare providers in the US now offer an online patient portal. The most widely used platform is MyChart (by Epic), but your provider may use a different system. Here’s how to check:
- Log in to your provider’s patient portal (e.g., MyChart, athenahealth, or your hospital’s custom portal)
- Navigate to Test Results, Lab Results, or Health Summary
- Look for entries related to “blood type,” “ABO group,” or “Rh factor”
- If you don’t see it there, check the Immunizations & Health History or Documents section
Keep in mind that your blood type will only appear in these records if you’ve had it specifically tested before. A routine CBC (complete blood count) does not include blood typing unless it was specifically requested.
Requesting Records Directly
If you don’t have portal access, you can call your doctor’s office or hospital and request a copy of your medical records. Under HIPAA law in the United States, you have the right to access your own health records, and providers must respond within 30 days.
Best for: People who have had surgeries, hospitalizations, prenatal care, or extensive medical history.
Cost: Free (with portal access). Small fee may apply for printed records.
Time: Instant if using a patient portal; up to 30 days if requesting paper records.
Method 2: Donate Blood (Free!)
Donating blood is one of the most popular ways to find out your blood type, and it’s completely free. Every blood donation is tested and typed before it enters the blood supply, and many donation centers will share your blood type with you afterward.
How It Works
When you donate blood at a Red Cross donation center, Vitalant, or another registered blood bank, your sample is tested for:
- ABO blood type
- Rh factor
- Infectious diseases (hepatitis B, hepatitis C, HIV, syphilis, and more)
- Antibody screening
After your donation, many organizations will send you a donor card or email notification with your blood type. The American Red Cross, for example, typically notifies donors of their blood type within a few weeks after the donation is processed.
How to Find a Blood Donation Center Near You
- Visit RedCrossBlood.org and use the donation center locator
- Go to Vitalant.org and search by ZIP code
- Check DonatingBlood.org for independent blood banks in your area
- Search “blood donation center near me” on Google Maps
The entire donation process takes about an hour, and you can book an appointment online in minutes. First-time donors are always welcome, and you leave knowing you’ve done something genuinely meaningful.
Best for: Anyone who wants a free, socially valuable way to find their blood type.
Cost: Free, and you’re helping save lives.
Time: You donate today; blood type results usually arrive within 1–4 weeks by mail or email.
Method 3: Use an At-Home Blood Typing Kit
If you want to find your blood type quickly without leaving home, an at-home blood typing kit is your best option. These kits are widely available online and at pharmacies, and most deliver results in under five minutes.
How At-Home Blood Typing Kits Work
Most at-home kits use a simple process called ABO agglutination:
- You prick your finger with the included lancet to get a small drop of blood
- You apply drops of blood to several wells on a test card, each containing different antibody reagents
- The reagents react with your blood antigens and cause visible clumping (agglutination)
- You compare the pattern of clumping to the included chart to determine your blood type
Results are typically clear within 2–5 minutes and are quite accurate when used correctly. Most kits test for both the ABO type and the Rh factor, giving you your complete blood type (e.g., A+, O−, etc.).
Top At-Home Blood Typing Kits to Consider
- Eldoncard Blood Type Test: One of the most widely used at-home kits. Results in 2 minutes, tests ABO and Rh. Available on Amazon for around $10–$15.
- Bio-Rad Blood Typing Kit: Often used in educational settings. Very clear results and includes detailed instructions.
- Home Access Blood Type Test: A popular option available at major pharmacies.
These kits are easy to find on Amazon or at pharmacies like Walgreens, CVS, or Walmart. Search for “blood typing kit” to see current options and prices.
Tips for Accurate Results
- Read the instructions fully before starting
- Make sure your hands are clean and dry
- Use the lancet only once and dispose of it safely
- Apply enough blood to each well (a full drop, not a smear)
- Read results within the time window specified, usually 2–5 minutes
- If results are ambiguous, consider retesting or consulting a doctor
Best for: People who want fast, private, at-home results.
Cost: $10–$25 depending on the kit.
Time: Results in 2–5 minutes after collecting blood.
Method 4: Get Tested at a Doctor’s Office or Lab
If you want the most medically reliable result, the gold standard is a blood typing test ordered by your doctor or performed at a certified laboratory. This is the same test used before blood transfusions and organ transplants.
How to Get a Blood Type Test at a Lab
There are two main routes:
Through your primary care physician: Ask your doctor to include blood typing with your next routine blood draw. They’ll order a “blood type and screen” or “ABO/Rh typing” test. Results are typically available within 24–72 hours and will appear in your patient portal.
Through a direct-to-consumer lab service: Companies like Quest Diagnostics, LabCorp, and ARCpoint Labs allow you to order blood typing tests without a doctor’s referral in most states. You pay online, go to a nearby lab location, have blood drawn, and receive results digitally within 1–3 days.
Approximate Costs
- Through insurance (with a doctor’s order): Usually covered or low copay
- Quest Diagnostics (self-pay): Around $25–$50
- ARCpoint Labs: Typically $20–$35
- Urgent care clinic: Varies widely; call ahead for pricing
This method is the most accurate and produces medically certified results. If you need your blood type confirmed for a surgical procedure, pregnancy care, or organ donation registration, this is the method to use.
Best for: People who need an official, certified blood type result for medical purposes.
Cost: $20–$50 without insurance; often covered with insurance.
Time: 1–3 business days for lab results.
Method 5: Check Your Birth Records or Baby Book
This is a method many people overlook. When you were born, hospital staff typically performed basic newborn bloodwork, including, in many cases, blood typing. This information may appear in:
- Your hospital birth records (contact the hospital where you were born)
- Your baby book or other childhood health records kept by your parents
- Your pediatrician’s records if they’re still available
- A newborn screening card (the heel prick test done within 24–48 hours of birth), some states retain these for years
How to Request Birth Hospital Records
- Contact the hospital’s medical records department by phone or their website
- Request your birth and newborn records (you’ll need to verify your identity)
- Ask specifically whether blood typing was performed and documented
Keep in mind that some older records may not be digitized or could have been destroyed after a certain number of years. But if your hospital uses electronic health records, even older information may be retrievable.
Best for: People who want to dig into existing records and potentially find results from birth.
Cost: Varies, some hospitals provide free digital records; others charge a small fee for copies.
Time: Anywhere from a few days to a few weeks depending on the hospital’s records department.
Method 6: Check Military or Government Records
If you or a parent served in the military, blood type is always recorded, it’s stamped on military dog tags and documented in service records. This is because knowing a soldier’s blood type is critical in combat medical situations.
For Veterans and Active Service Members
Your blood type should appear on your military ID or dog tags. It’s also part of your military medical records, which can be requested through:
- The National Personnel Records Center (NPRC): request via archives.gov/veterans
- The VA’s My HealtheVet portal: myhealthevet.va.gov
- Your branch’s official records request system (e.g., HRConnect for Army)
If you’re checking records for a deceased family member to learn about inherited blood type tendencies, the NPRC can also process next-of-kin requests with appropriate documentation.
Best for: Veterans, active duty service members, or their family members.
Cost: Free for veterans requesting their own records.
Time: Can take several weeks for mailed records requests; faster via online portals.
Blood Type Compatibility: What You Should Know
Once you know your blood type, it’s worth understanding what that means for transfusions, donations, and pregnancy.
Blood Transfusion Compatibility
Not all blood types are compatible with each other. Receiving incompatible blood can trigger a potentially fatal immune reaction. Here’s a quick compatibility overview:
- O− (O negative): Universal donor. Can give red blood cells to anyone. But can only receive O− blood.
- AB+ (AB positive): Universal recipient. Can receive red blood cells from any blood type.
- O+: Can donate to all Rh+ types (A+, B+, AB+, O+). Very useful in emergencies.
- A+: Can donate to A+ and AB+ recipients.
- B+: Can donate to B+ and AB+ recipients.
For plasma donations, the compatibility rules are reversed, AB is the universal plasma donor.
Blood Type and Pregnancy
Rh incompatibility during pregnancy occurs when an Rh-negative mother carries an Rh-positive baby (inherited from the father). The mother’s immune system can develop antibodies against the baby’s blood, which can cause problems in future pregnancies.
This is why doctors routinely test blood type and Rh factor early in pregnancy. If you’re Rh-negative and pregnant, your doctor will likely recommend Rh immunoglobulin (RhoGAM) injections to prevent complications. Knowing your blood type in advance can help you have this conversation with your OB-GYN from the start.
Blood Type and Organ Donation
Blood type is one of the primary factors in organ matching. When you register as an organ donor (via your state’s DMV or DonateLife.net), your blood type becomes part of your donor profile. Knowing and recording your blood type ensures your organ donor registration is as complete and useful as possible.
Frequently Asked Questions
Can I find out my blood type from a DNA test like 23andMe or AncestryDNA?
Yes and no. Some consumer DNA services can identify certain genetic markers associated with blood type, but these tests are not designed for medical blood typing and results may not be fully accurate. For a reliable blood type result, use one of the six methods described above, particularly a lab test or at-home typing kit.
Can my blood type change over time?
Under normal circumstances, no, your blood type is determined by genetics and remains the same throughout your life. However, in very rare cases, certain medical events like bone marrow transplants can alter a person’s blood type to match the donor’s. Disease can also sometimes affect blood type expression, though this is extremely uncommon.
What is the rarest blood type?
AB-negative (AB−) is the rarest common blood type, found in less than 1% of people. However, the rarest blood type overall is called “Rh-null,” sometimes called “golden blood,” which lacks all Rh antigens. Only about 43 people worldwide are known to have it.
Is blood type inherited from your parents?
Yes. Blood type is determined by the genes you inherit from both parents. Each parent passes on one gene for the ABO system and one for the Rh factor. For example, two parents with type O blood will always have type O children, because O is recessive. Blood type inheritance follows basic Mendelian genetics, so knowing your parents’ blood types can sometimes narrow down your own, though a direct test is always more reliable.
Do hospitals always check blood type before a transfusion?
Yes, absolutely. Hospitals always perform a “type and screen” or “type and crossmatch” test before administering a blood transfusion, even if the patient’s blood type is already known. This is a critical safety protocol to confirm compatibility and prevent a transfusion reaction.
Can I find out my blood type from a urinalysis or saliva test?
Technically, about 80% of people are “secretors”, meaning they express blood group antigens in bodily fluids like saliva. Some specialized tests can detect blood type from saliva, and certain at-home kits use this method. However, saliva-based testing is less common and generally less accurate than blood-based testing. A standard blood test remains the most reliable method.
How accurate are at-home blood typing kits?
When used correctly, at-home blood typing kits from reputable brands like Eldoncard are generally accurate for ABO and Rh typing. However, they are not considered medically certified results. If you need your blood type confirmed for surgery, donation, or pregnancy care, always use a lab-based test.
What should I do once I know my blood type?
A few smart steps: record it in your phone’s medical ID (both iPhone and Android have this feature), add it to your emergency contact information, tell your doctor so it’s in your file, and consider registering as a blood or organ donor. If you’re type O−, consider donating blood regularly, your blood is especially valuable in emergencies.
Conclusion
Finding out your blood type doesn’t have to be complicated or expensive. Whether you check your MyChart portal, donate blood for free, order a quick at-home kit, or ask your doctor during your next visit, you have plenty of options to choose from.
Here’s a quick summary of all six methods:
- Check medical records / patient portal: Free and instant if you’ve been tested before
- Donate blood: Free, takes a few weeks, and helps save lives
- At-home blood typing kit: $10–$25, results in minutes, available on Amazon
- Doctor’s office or lab test: Most accurate, $20–$50 without insurance
- Birth or hospital records: Free or low-cost, requires contacting the hospital
- Military or government records: Free for veterans, useful for family history
For most people, the fastest route is either checking their patient portal (free) or ordering an at-home kit (under $25, results in minutes). If you need an official result for medical reasons, go with a lab test. If you don’t have a regular doctor yet, our guide on how to find a good doctor can help.
Now that you know how to find your blood type, you’re better prepared for medical emergencies, more informed about your health, and potentially ready to become a life-saving blood donor. Take the next step today, it only takes a few minutes and could matter more than you know.