Blood can play a huge role in your health, and yet many people don't know their blood type — or haven't even discussed the topic with a doctor. A 2019 survey by Quest Diagnostics, a clinical laboratory company, found that 43% of Americans don't know their blood types. "Most people actually don't know their blood type unless they've had some type of procedure done or a recent visit that required a blood type [test]," explains Tiffany Lowe-Payne, DO, a North Carolina-based osteopathic family physician, who also serves as an assistant professor at Campbell University School of Osteopathic Medicine.

But a recent revelation in research during the novel coronavirus pandemic has people suddenly very interested in understanding which kind of blood pumps through their veins. According to research published in the New England Journal of Medicine in June, data suggests that people with Type A blood may be at greater risk for contracting COVID-19 and experiencing severe symptoms, while people with Type O blood have a lower risk. However, another study published in July counters some of these findings, illustrating a lack of concrete evidence in a connection between blood type and COVID-19. And Lowe-Payne emphasizes that any blood type is susceptible to severe symptoms, despite these studies.

But there are other diseases and risks outside of the pandemic that may also be influenced by your blood type. Certain blood types are associated with higher risks for a string of cancers, based on data pulled from the Dana-Farber Cancer Institute, for example. Those with AB and A blood types are also more likely to develop stomach cancer, per a recent study published in BioMed Central Cancer. And according to experts at the University of Pennsylvania, those with A, B, and AB blood types also have a 6% greater risk of developing coronary heart disease; the same blood types are also linked to an 82% greater likelihood of developing memory issues, compared to Type O.

More From Good Housekeeping

preview for Featured Videos From Good Housekeeping US

It's clear that blood type, among other aspects of inherited genetics, may influence your health more than you know — an important topic to discuss with your doctor. There are a few simple ways you can find out your blood type before discussing any potential risks with your healthcare provider.

Why should I know my blood type?

Your blood type is something you're born with, and it's determined by your parents' genetics — specifically, whether or not certain antigens are present in your body, according to the American Red Cross. Put simply, an antigen is a substance that prompts an immune response in the body; it triggers your immune system to get into gear.

The main blood groups are based on the presence or absence of two antigens, A and B, on the surface of our red blood cells. People with neither A or B antigens have what's called Type O blood. The protein rhesus (also known as Rh) factor may also be present, known as positive, or absent, known as negative.

blood type compatibility chart which blood type can i donate

The eight common blood types: A+, A-, B+, B-, O+, O-, AB+, and AB-.

In the United States, O+ is the most common blood type, found in about 37% of the population, followed by A+ in around 36% of people, according to the Stanford School of Medicine Blood Center. AB- is the rarest, occurring in less than 1% of Americans. The Red Cross considers people with Type O- blood the "universal blood donor," because it can be used in emergency blood transfusions for any other blood type.

But do you really need to know your blood type? For most people, it isn't actually very important, says Stephanie Lee, M.D., president of the American Society of Hematology and associate director of the Clinical Research Division at the Fred Hutchinson Cancer Research Center in Seattle. "I think it's good in general to know about your health, but specifically, the two areas where [blood type] comes up would be transfusion or in pregnancy," says Dr. Lee, who is also a professor at the University of Washington.

She explains that medical teams don't rely on you sharing your blood type before any major operation or blood transfusion; they'll test your blood type beforehand. Pregnant women, in particular, routinely undergo blood-type tests to determine their Rh factor, and whether it is compatible with their baby. If a new mom has Rh-negative blood and their baby is found to be developing Rh-positive blood types, it could cause a number of complications, including miscarriage, if it's not caught early during pregnancy. Doctors can often administer what's called a RhoGAM shot to offset any problems with Rh compatibility.

How to find out your blood type

The easiest way is to quickly check your birth certificate, since blood type is sometimes listed in birth records, Dr. Lee says. But if you don't have access to that information, there are a few different ways to learn which blood type is running through your veins:

Ask your doctor for a blood type test: A simple lab test from your primary care physician can reveal your blood type, Lowe-Payne says. But you'll have to specifically ask for it, since it's not part of routine exams or wellness checks. And insurance providers may not cover it, unless there's a medical reason for the test, she adds. So patients will most likely have to pay out of pocket if they request blood work solely to discover their blood type.

If you've previously had any blood work done with your primary care provider, they may already have your blood type on file. This is also true for any trip to an urgent care clinic, like CVS' MinuteClinic, if you've had blood drawn during an unplanned visit. A request to your physician's office never hurts!

Buy an at-home blood type kit: Do a quick Google search and you'll find a slew of at-home blood type testing kits at a variety of price points. Some ask for a small amount of blood from a finger prick or saliva. But many of the tests haven't been directly evaluated by the U.S. Food and Drug Administration.

Blood Type (ABO, Rh) Test

Quest Diagnostics Blood Type (ABO, Rh) Test

Now 74% Off

"There are no FDA-approved blood type tests with a specific indication for home use to determine ABO/Rh blood type," an FDA spokesperson tells Good Housekeeping. "There are FDA-cleared tests intended for individual blood group determination for educational and informational purposes only. These tests are not intended to be used for blood donation or transfusion testing."

Tests without FDA clearance or approval may not offer truly accurate results, the spokesperson says, and you may also have trouble reading test results yourself. At-home kits available from retailers like Amazon (this kit averages 4-stars with more than 2,300 reviews) could provide you an idea of a general blood type, Lowe-Payne explains, but she isn't sure of their accuracy. The most accurate home tests may come from laboratories that conduct blood work on behalf of your provider, such as QuestDirect.

Donate blood to help others: "Donating blood is an easy way for individuals to find out what their blood type is," says Prabhakar Borge, M.D., chief medical officer of the American Red Cross. Every unit of blood donated through the organization is tested to identify the donor's blood group and Rh type, he adds. Blood donors receive a blood donor card or can create an online donor profile, listing their blood type.

Donors don't need to know their blood type before donating, but it's helpful to know. For example, Type O individuals are especially encouraged to donate because it's most common and is the universal blood type, but is often in short supply and high demand. The COVID-19 pandemic has increased the need for blood donations, with cases growing and many blood drives canceled, Dr. Borge explains: "This has caused hundreds of thousands of blood donations to go uncollected."

Not only is donating blood free, Lowe-Payne says, but "you're saving somebody's life in the process."

Want to donate blood, but don't know where to start? Make an appointment to visit a nearby American Red Cross blood drive, where you'll be able to donate blood or platelets based on eligibility requirements (in most cases, you need to be in good health and at least 16 years old). You may also donate blood through America's Blood Centers in areas where the Red Cross isn't holding a drive. You and your family, office, or school may team up to host a blood drive in your community through the Red Cross as well.