How to Tell If You Have a Blood Clot

How to Tell If You Have a Blood Clot: Signs, Symptoms, and More

What is a blood clot?


  1. An immobile blood clot generally won’t harm you.
  2. If a blood clot breaks free and travels to your heart and lungs, it could become dangerous.
  3. Blood clots are most commonly found in the lower leg.

A blood clot is a mass of blood that changes from liquid to a gel-like or semisolid state. Clotting is a necessary process that can prevent you from losing too much blood in certain instances, such as when you injure or cut yourself.

When a clot forms inside one of your veins it won’t always dissolve on its own. This can be a very dangerous and even life-threatening situation.

Deep vein thrombosis (DVT) is a clot that occurs in one of the major veins deep inside your body. It’s most common for this to happen in one of your legs, but it can also happen in your arms, pelvis, lungs, or even your brain.

An immobile blood clot generally won’t harm you, but there is the chance that it could move and become dangerous. If a blood clot breaks free and travels through your veins to your heart and lungs, it can get stuck and prevent blood flow. When it travels to your lungs, it’s called a pulmonary embolism (PE), which is a medical emergency.

The American Society of Hematology estimates that DVT affects up to 900,000 Americans each year. It kills approximately 100,000 Americans annually. There’s no one way to know whether you have a blood clot without medical guidance. If you know the most common symptoms and risk factors, you can give yourself the best shot at knowing when to seek an expert option.

Early warning signs and symptoms


It’s possible to have a blood clot with no obvious symptoms. When symptoms do appear, some of them are the same as symptoms of other diseases. Here are the early warning signs and symptoms of a blood clot in the leg, heart, abdomen, brain, and lungs.

You should call your doctor immediately if you think you might have a blood clot. A healthcare professional will be able to look at your circumstances and let you know what steps to take from there.

Blood clot in the leg

blood clots - legs

The most common place for a blood clot to occur is in your lower leg, says Akram Alashari, M.D., a trauma surgeon and critical care physician at Grand Strand Regional Medical Center in Myrtle Beach, South Carolina.

A blood clot in your leg can have various symptoms, including:

  • swelling
  • pain
  • tenderness
  • a warm sensation
  • pain in your calf when you stretch your toes upward
  • a pale or bluish discoloration

Your symptoms will depend on the size of the clot. That’s why you might not have any symptoms or you might only have minor calf swelling without a lot of pain. If the clot is large, your entire leg could become swollen with extensive pain.

It’s not common to have blood clots in both legs at the same time. Your chances of having a blood clot increase if your symptoms are isolated to one leg.

Blood clot in the heart

blood clot - heart

The heart is a less common location for a blood clot, but it still can happen. A blood clot in the heart could cause your chest to hurt or feel heavy. Light-headedness and shortness of breath are other potential symptoms.

Blood clot in the abdomen

blood clot - abdomen

Severe abdominal pain along with vomiting and diarrhea could be symptoms of a blood clot somewhere in your abdomen. These also could be symptoms of a stomach virus or food poisoning.

Blood clot in the brain

blood clot - brain

A blood clot in your brain could cause a sudden and severe headache along with some other symptoms, including sudden difficulty speaking or seeing.

Blood clot in the lungs

blood clot - lungs

A blood clot that travels to your lungs is called pulmonary embolism (PE). Possible symptoms that could be a sign of a PE are:

  • sudden shortness of breath that can’t be explained by exercise
  • chest pain
  • palpitations, or rapid heart rate
  • breathing problems
  • coughing up blood

Check out: What does it feel like when you have a blood clot? »

What are the risk factors?

Risk Factors

Certain risk factors increase your chances of having a blood clot. A recent hospital stay, especially one that’s lengthy or related to a major surgery, increases your risk of a blood clot.

Common risk factors that can put you at a moderate risk for a blood clot include:

  • age, especially if you are over the age of 65
  • lengthy travel, such as any trips that caused you to sit for more than four hours at a time
  • bed rest or being sedentary for long periods of time
  • obesity
  • pregnancy
  • a family history of blood clots
  • smoking
  • certain birth control pills

When to call a doctor

when to see a doctor

Diagnosing a blood clot by symptoms alone is very difficult. According to the Centers for Disease Control and Prevention, almost 50 percent of people with DVT have no symptoms. This is why it’s best to call your doctor if you’re concerned for any reason that you might have one.

Symptoms that come out of nowhere are especially concerning. Call your local emergency services immediately if you experience any of the following:

  • sudden shortness of breath
  • chest pressure
  • difficulty breathing, seeing, or speaking

Your doctor or other healthcare professional will be able to tell whether there’s cause for concern and can send you for more tests to determine the exact cause. In many cases, the first step could be a noninvasive ultrasound. This test can show an image of your veins, which can help your doctor make a diagnosis.

Keep reading: Is it a blood clot or a bruise? »

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