How to diagnose a blood clot

When blood vessels are damaged, your body’s ability to clot prevents excess blood loss. Forming a clot is also the first step in healing the injury.

Sometimes a blood clot forms when a blood vessel is not needed and blocked. This stops blood from entering the organs attached to the blood vessels. When their blood supply is cut off, the organs are damaged and stop working.

Symptoms of organ damage can be the first clue that someone has a blood clot. In some cases, blood clots can be life-threatening rather than life-saving. That’s why it’s very important to find out if there is one.

In this article, you’ll learn how a healthcare provider diagnoses a blood clot.

type of blood clot

There are two types of blood clots that can cause serious health problems: blood clots and emboli.

A sort of thrombus A blood clot that forms in a blood vessel.One embolus A blood clot that travels through a blood vessel and causes blockage elsewhere in the body.

Blood clots can damage tissue because they block blood flow through blood vessels. Diseases such as stroke occur when tissues cannot get oxygen and nutrients from the blood.

Blood clots or emboli can lead to a variety of health conditions:

  • Strokes often occur because of blood clots in the arteries leading to the brain. This can also happen if an embolus enters the brain. These clots usually start in the heart or an artery in the neck (carotid artery).
  • Heart attacks are usually caused by blood clots that form in the arteries of the heart. It usually consists of a substance called atherosclerotic plaque.
  • Deep vein thrombosis (DVT) is a clot that forms in one of the main veins in the legs, thigh or pelvis.
  • A pulmonary embolism is a blood clot that enters the lungs. It usually starts with a DVT.
  • A blood clot in the main vein that drains the liver (portal vein thrombosis).
  • Blood clots in the veins that drain the kidneys (renal vein thrombosis).

Treatment of a blood clot depends on its location. One of the most common treatments is a drug called a blood thinner.

These drugs are good at breaking down clots or preventing them from getting bigger. However, they also have serious side effects. People who take blood thinners are at risk for bleeding problems.


The health problems caused by blood clots depend on where they form. When the blood supply to the organ is blocked by a clot, it can damage the organ. A blood clot that forms in one place can also travel through the bloodstream and cause blockages elsewhere.

How blood thinners work

lab testing

Health care providers can use some lab tests to diagnose imprinted clots. These tests can tell if your body’s blood clotting system isn’t working properly.

D-dimerization experience blood

The D-dimer blood test can tell if there has been abnormal clotting activity somewhere in the blood recently. This test can help providers determine the diagnosis of DVT or pulmonary embolism.

Cardiac Biomarkers

Cardiac biomarkers help diagnose heart attack. While blood tests cannot specifically diagnose blood clots, they can tell if the heart muscle is damaged. This damage may be caused by plaque in the coronary arteries that has become clotted and ruptured.


A blood test can show if there is abnormal clotting activity in the body. They can also show if the heart has been damaged by a clot.

COVID and blood clots

imaging test

Imaging tests can help find blood clots. Some tests can look for damage from blood clots. There are also tests that can tell if you are at risk for blood clots.

compression ultrasound

Compression ultrasound testing can be used to diagnose DVT. The test is non-invasive, which means there are no needles or incisions. The ultrasound wand is passed over the part of your body that your provider wants to photograph.

V/Q scan

in a ventilation-perfusion Scan (V/Q scan), in which a special dye is injected into the blood. It makes it easier to see how blood flows in and out of the lungs. This test can be used to see if blood vessels in the lungs are blocked by emboli.

CT scan

A computed tomography (CT) scan is a type of X-ray. It provides very detailed pictures of the inside of the body.

For example, CT scans can help providers see if the brain has been damaged by a stroke. It can also look at the lungs to see if they have been damaged by a pulmonary embolism (PE).

MRI scan

MRI scans help to see if a person has early organ damage after a stroke, PE, portal vein thrombosis, or renal vein thrombosis.

However, MRI takes longer than other imaging tests. If a person needs immediate care, the provider may use a CT scan.


Imaging tests can help find blood clots. They can also show organ damage from the clot.

Can you prevent blood clots?


There are some other test providers that can be used to look for blood clots. These tests use imaging, but there are some extra steps.

Angiography or venography

Angiography and venography is an imaging procedure that uses special dyes to help “illuminate” the inside of the body. The dye is injected into a blood vessel that the provider thinks has a clot in it. The imager is then used to take pictures of the boat.

There are also versions of these tests that look for specific types of blood clots:

  • Pulmonary angiography can be used to diagnose pulmonary embolism.
  • Venography is used to diagnose DVT.
  • Cardiac angiography looks for clots in the coronary arteries.
  • Carotid angiography looks for damage or clots in the blood vessels in the neck called the carotid arteries.


An echocardiogram checks the heat and learns how it works. Providers can also use them to see if a blood clot has formed in the heart.

Having certain heart conditions can make blood clots more likely to appear in certain places. For example, in people with atrial fibrillation, a clot is usually found in the left atrium of the heart.people who are expanding cardiac diseasethe clot appears in the left ventricle.

An echocardiogram can also reveal problems that may make it easier for emboli to pass in and out of the heart.An example of this condition is a birth defect, called Patent foramen ovale.

The test can also be used to determine if someone is at risk of having a stroke due to an embolus.


Some tests use dyes to “illuminate” the inside of the body. The scanned photos show how blood flows through the body. They can also spot organ problems that may make it easier for imprinted clots to form or move.


A blood clot can be a life-threatening condition. Sometimes, people don’t know they have a blood clot. However, people often experience symptoms because the clot can damage organs and tissues.

If healthcare providers think someone has a blood clot, they can run different tests to make a diagnosis. Lab tests and imaging tests can also help providers determine the type of clot a person has.

Providers can also use tests to determine if someone is at risk of developing a blood clot. If they are, they may need to take medication to help prevent the formation.

VigorTip words

Your body’s ability to make blood clots can save lives. However, if the clot forms when it is not needed, it can be life-threatening. Knowing if you have a blood clot is important because it can damage your body and cause serious health problems.

There are many tests that healthcare providers can use to determine if you have a blood clot. Some can also help determine if you are at risk for blood clots.

Seek immediate medical attention if you have symptoms that may be from a blood clot.

Frequently Asked Questions

  • Can a blood test show a blood clot?

    Yes. A D-dimer blood test can help determine if a blood clot has occurred. It can identify deep vein thrombosis (DVT) or pulmonary embolism (PE). Cardiac biomarkers can be used to see if the heart muscle is damaged. This may suggest that a blood clot has formed in the blood vessels of the heart.

  • Which tests look for blood clots in the legs?

    Laboratory tests and imaging tests can show signs of blood clots in the legs or deep vein thrombosis elsewhere in the body. Here are some tests your provider may perform to look for blood clots in your legs:

    • D-dimer blood test
    • pressurized ultrasound
    • Contrast venography
    • Computed tomography (CT) scan
    • Magnetic Resonance Imaging (MRI) Scan
  • What tests can detect blood clots in the lungs?

    Providers may use one or more of the following tests to look for clots in the lungs:

    • V/Q scan
    • Pulmonary angiography
    • Computed tomography (CT) scan
    • Magnetic Resonance Imaging (MRI) Scan
  • How can I tell if I have a blood clot?

    A blood clot without symptoms is possible. However, people tend to have some warning signs. Symptoms that may indicate that you have a blood clot include:

    • skin tenderness, redness, and warmth in one area of ​​the body
    • swelling (usually only in one leg)
    • shortness of breath
    • chest pain
    • Dizziness

Medications to treat blood clots