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If You Have This Blood Type, Be Worried About Blood Clots

What are blood clots and how to avoid them.
FACT CHECKED BY Emilia Paluszek

According to the CDC, 900,000 Americans a year are affected by blood clots, resulting in nearly 100,000 deaths. While blood clotting is a vital function for wound healing and preventing bleeding, clots can be life-threatening if they form in the wrong place or don't dissolve. Here are the blood types most likely to be affected by blood clots, according to doctors. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What Exactly Are Blood Clots?

blood clot

Blood clots are partially solidified bits of blood which form in blood vessels such as your arteries, veins, and capillaries. "A blood clot, or thrombus, can move through the bloodstream until it gets stuck in a narrow passageway, becoming what is called an embolus," warns the American Heart Association. "The blood can no longer pass through the veins and reach organs. An embolus in a coronary artery can cause a heart attack, in a cerebral artery, it can cause a stroke."


Blood Clots and COVID-19

Infected patient in quarantine lying in bed in hospital.

There is growing evidence that blood clots are connected to COVID-19. "When you, say, fall and skin your knee, it turns your immune system on, and one of the ways your immune system reacts to an injury is by making your clotting system more active," says Matthew Exline, MD, medical director of the medical intensive care unit at the Ohio State Wexner Medical Center. "It kind of makes sense that your body would say, if I see an infection, I need to be ready to clot. But when the infection is as widespread and inflammatory as COVID-19, that tendency to clot can become dangerous."


Arterial Blood Clots

closeup man's chest heart attack

Arterial clots occur when a blood clot blocks an artery, but are (thankfully) a relatively rare occurrence. "They are a whole different beast," says vascular medicine specialist Michael Tran, DO. "The clot can block oxygen from reaching the heart or brain, leading to a heart attack or stroke."



older woman symptoms heart failure

Signs and symptoms of blood clots include pain and swelling, shortness of breath, chest pain, and spasms and cramps. "Everyone has different symptoms that can range from none to severe," says Dr. Tran. "But there are common signs and symptoms of blood clots to be aware of."


Blood Types A and B Are Most At Risk

lab assistant holding test tube with blood while standing in

People with blood types A, B, or AB are more likely to get blood clots, experts warn. "While people cannot change their blood type, our findings may help physicians better understand who is at risk for developing heart disease," says Lu Qi, Ph.D. "It's good to know your blood type in the same way you should know your cholesterol or blood pressure numbers. If you know you're at higher risk, you can reduce the risk by adopting a healthier lifestyle, such as eating right, exercising, and not smoking."


How to Stay Safe Out There


Follow the public health fundamentals and help end this pandemic, no matter where you live—get vaccinated or boosted ASAP; if you live in an area with low vaccination rates, wear an N95 face mask, don't travel, social distance, avoid large crowds, don't go indoors with people you're not sheltering with (especially in bars), practice good hand hygiene, and to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan