d-dimer test

test overview

a d-dimer test is a blood test that measures a substance that is released when a blood clot breaks up. doctors order the d-dimer test, along with other lab tests and imaging scans, to help check for blood-clotting problems. a d-dimer test can also be used to check how well a treatment is working.

why it is done

doctors use the d-dimer test when a person might have a dangerous blood-clotting problem. these problems include:

how to prepare

no special preparation is required before having this test.

how it is done

a health professional uses a needle to take a blood sample, usually from the arm.

watch

how it feels

when a blood sample is taken, you may feel nothing at all from the needle. or you might feel a quick sting or pinch.

risks

there is very little chance of having a problem from this test. when a blood sample is taken, a small bruise may form at the site.

results

each lab has a different range for what's normal. your lab report should show the range that your lab uses for each test. the normal range is just a guide. your doctor will also look at your results based on your age, health, and other factors. a value that isn't in the normal range may still be normal for you.

• a low or normal d-dimer test result means that there is very little of the substance that's released as a blood clot breaks up. having very little of this substance means that a blood clotting problem isn't likely.
• a higher-than-normal d-dimer level might mean that there is a blood-clotting problem. but a higher level might be caused by some other health problem or by a normal healing process.
• d-dimer levels are often higher than normal in people who have abnormal blood clotting.