I. What Is D-Dimer Testing?

Around 7% to 11% of Americans diagnosed with DVT or a PE die, making D-dimer testing a valuable tool for diagnosing clotting disorders before they become fatal.

Why should you get tested?

You should have the D-dimer test if you have any symptoms of a clotting disorder, including leg swelling and tenderness, chest pain, or trouble breathing.

Who should get tested?

You’ll need this test if you have symptoms of a clotting disorder or an elevated risk of developing a clotting disorder.

When to get tested

You should have a D-dimer test as soon as possible after experiencing shortness of breath, chest pain, and other emergent symptoms.

II. How to Prepare for D-Dimer Testing

No special preparation is needed for the D-dimer test. If your doctor ordered other tests, such as a glucose test, you may have to fast overnight or schedule an appointment to have blood drawn at a specific time of day. It’s also a good idea to drink plenty of water before your test, as the extra fluid makes it much easier for a phlebotomist to find a vein.

III. How a D-Dimer Test Works

If your doctor orders the D-dimer test, expect to give a blood sample. You can visit an outpatient laboratory or have the blood drawn at your doctor’s office, whichever is more convenient. You may have to register first, so be sure to have your ID card and your insurance card with you.

After you register, a phlebotomist — a person trained to draw blood — will review the order and prepare to draw your blood. This involves tying a tourniquet around your arm and palpating the skin to find a vein. The phlebotomist may ask you to make a fist or open and close your hand repeatedly to make your veins easier to see and feel. Next, the phlebotomist will cleanse your skin with an alcohol wipe and insert a needle through the skin and into the vein. Blood collected in a specimen tube is sent to the laboratory and analyzed to determine how much D-dimer is in it.

IV. Understanding D-Dimer Testing Results

How the results are delivered depends on your doctor. Some providers have patient portals where you can download the results on your computer or mobile device. Others deliver test results by mail or over the telephone. A D-dimer level less than 0.50 is considered normal. If your D-dimer level is higher than that, your doctor may order other tests designed to check for clotting disorders, such as a platelet count or a prothrombin time. In some cases, imaging studies are necessary to see if you have a blood clot in one of your veins.

How long it takes to receive the results also depends on your doctor. A laboratory can complete the test in just a few hours, but it may take your doctor several days to receive the report, review it, and contact you with an update.

V. Learn From Our D-Dimer Test Sources

Want to know more about D-dimer testing? Learn from the sources used in this guide.