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Many people assume their blood type is somewhere in their medical records — but it often isn't. Here's when it gets recorded, when it doesn't, and exactly how to find out your blood type.
Many people assume their blood type is somewhere in their medical records — but it often isn't. Here's when it gets recorded, when it doesn't, and exactly how to find out your blood type.
You open your patient portal, scroll through lab results, and search for your blood type. Nothing comes up. You check your health summary. Still nothing. You assumed it was there — filed away alongside your cholesterol numbers and vaccination dates. It wasn't.
Blood type is one of those details everyone thinks their doctor has on record. Most don't. The reason is straightforward: blood typing is not part of a standard lab panel. Unless you have been pregnant, donated blood, had surgery, or served in the military, there is a decent chance no one has ever tested yours.
This guide covers when blood type gets recorded, when it does not, how to track it down, what the Rh factor means for pregnancy, and what to do when your records come up empty.
Your blood type shows up in your records only if something triggered the test. Here are the situations where blood typing is nearly always performed and documented:
Surgery. Before any major operation under general anesthesia, the hospital runs a type and screen — determining your blood type and checking for unexpected antibodies. That result lands in your hospital chart. If you have had surgery at a hospital, your blood type is very likely in that facility's records.
Blood transfusion. If you have received donated blood, your blood was typed first. Giving the wrong type can be fatal. There is no flexibility here.
Pregnancy and prenatal care. Blood type testing is standard in first-trimester labs. Every pregnant patient gets typed, primarily to determine Rh factor status. If you have been pregnant, your OB's records almost certainly include your blood type.
Military service. The U.S. military blood-types every service member during initial processing. It is stamped on your dog tags. If you served, this information is in your military medical records.
Blood donation. Blood banks type every donation as part of screening. Many send you a donor card with your blood type. If you donated even once, you can call and ask.
Organ transplant evaluation. Anyone evaluated for organ donation or transplant gets extensively typed — not just ABO and Rh, but additional compatibility markers.
If none of the above applies to you, your blood type is probably not on file anywhere.
Routine blood panels — the kind ordered at your annual physical — check cholesterol, blood sugar, kidney function, thyroid hormones, and complete blood count. Blood type is not on that list. There is no clinical reason to include it for a healthy adult who is not facing surgery or pregnancy.
Your blood type does not change how a primary care doctor manages your treatment at a routine visit. They need it only when a procedure is imminent. At that point, they test it themselves — they will not rely on old records or what you tell them.
The practical result: many healthy adults in their 20s and 30s who have not had surgery or children have no blood type on record. If you are one of them, this is normal. Not an oversight.
Log into your health system's patient portal (MyChart, Healow, FollowMyHealth, or your hospital's portal). Look under "Health Summary," "Medical Records," or "Labs & Results." Search for "blood type," "ABO," or "Rh factor."
If you have had surgery or given birth at this health system, the result should appear in your surgical history or as a lab result from a type and screen order.
Call your primary care physician, OB-GYN, or surgeon's office and ask whether your blood type is on file. This takes about two minutes. Staff can usually check while you hold. If you gave birth at their affiliated hospital, they may be able to pull it from the shared record.
Call the medical records department at any hospital where you had surgery or delivered a baby. Request the "type and screen" result from that encounter. You have a legal right to this information under HIPAA, and they can usually provide it quickly — often over the phone or through a records request.
If you have ever donated blood — even once, even decades ago — call the organization you donated through (the American Red Cross, Vitalant, OneBlood, your regional blood center). Give them your name and date of birth. They will have your blood type on file.
The American Red Cross also lets you check through your online donor account.
Some birth certificates issued decades ago included blood type, though this is rare for anyone born after the 1980s. Worth checking if you have your original.
If you served in the military, your blood type is in your military health records and on your DD-214 discharge papers.
At-home blood typing kits cost $10-$20 and are available online and in some pharmacies. Brands like EldonCard provide a lancet, reagent cards, and instructions. You prick your finger, place a drop of blood on each reagent zone, and read the pattern within five minutes.
These kits are generally accurate. But they should not be treated as the basis for any medical decision. Before surgery or a transfusion, hospital staff will always run their own typing — they do not accept self-reported results.
Ask your doctor to add a blood type test the next time they order labs. It is an inexpensive add-on. Once the result is in your chart, it appears in your patient portal and becomes available to future providers.
Blood type has two parts: the ABO group (A, B, AB, or O) and the Rh factor (positive or negative). The ABO group identifies which antigens sit on your red blood cells. The Rh factor tells you whether you carry a specific protein called the Rh antigen.
About 85% of people are Rh-positive. The remaining 15% are Rh-negative. For day-to-day health, this gap does not matter.
During pregnancy, it can matter a great deal.
Rh incompatibility occurs when a Rh-negative mother carries a Rh-positive baby (possible if the father is Rh-positive). If the mother's blood contacts the baby's Rh-positive blood — during delivery, miscarriage, amniocentesis, or trauma — her immune system may produce antibodies against the Rh antigen. The first pregnancy is usually unaffected. But in later pregnancies, those antibodies can cross the placenta and attack a Rh-positive baby's red blood cells, causing hemolytic disease of the newborn. This is serious.
All pregnant patients are blood-typed in the first trimester for this reason. Rh-negative mothers receive Rh immunoglobulin (brand name: RhoGAM) around week 28 and again after delivery. The injection prevents the antibody response.
If you are Rh-negative, this ranks among the most important health details you can document. Make sure it appears in your records.
If your blood type is on file, here is what the notation looks like — a combination of your ABO group and Rh factor:
In an EHR system, blood type typically appears in the "Problem List" or "Health Summary" section, or as a lab result under "Type and Screen" or "ABO/Rh."
The type and screen test goes slightly beyond a basic blood type test. It includes the ABO/Rh result plus a check for unexpected antibodies (the antibody screen). Hospitals order it before any surgery or transfusion.
Blood type has attracted pop culture claims for decades — blood type diets, personality profiling, relationship compatibility. Almost none of it holds up.
What the evidence does not support:
What research has found some association with:
These are population-level patterns, not individual predictions. No doctor would change your clinical care based on blood type alone, outside of transfusion, transplant, and pregnancy contexts. The gap between what blood type enthusiasts claim online and what the clinical evidence supports remains wide.
If you cannot find your blood type in any patient portal, old surgical record, military file, or blood bank database, the path forward is simple:
Knowing your blood type covers a narrow but specific set of situations where getting it wrong carries real consequences. Five minutes and a simple lab add-on puts the information where it belongs.
This information is educational and does not replace professional medical or legal advice.
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