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Deep Vein Thrombosis Health Center

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D-Dimer Test


The d-dimer test measures the amount of a substance that is released when a blood clot breaks up.

The normal values listed here (called a reference range) are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

D-dimer test1

Less than 250 micrograms per liter (mcg/L)

Less than 1.37 nanomoles per liter (nmol/L)

  • 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.

What To Think About

D-dimer test results may be affected if the person being tested has rheumatoid arthritis, has had recent surgery or trauma, is on estrogen therapy, or is pregnant.


  1. Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

Other Works Consulted

  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerJeffrey S. Ginsberg, MD - Hematology

Current as ofMarch 12, 2014

1 | 2

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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