Coagulation
D-Dimer
LOINC 30240-6 · ng/mL
What it is
D-dimer is a small fragment left behind when a blood clot breaks down. It rises when clots are forming and dissolving in the body.
Why it matters
It is mainly used to help rule out dangerous clots such as deep-vein thrombosis or a lung clot.
What high values can mean
A higher value can indicate clot activity, but also rises with infection, inflammation, surgery, pregnancy and age, so it is non-specific.
What low values can mean
A lower (normal) value makes a significant clot unlikely, which is its main strength.
How to improve it
D-dimer reflects an acute process; care addresses the underlying cause if a clot is found.
Food & lifestyle
No specific food changes D-dimer; staying active and hydrated supports healthy circulation generally.
Preparing for the test
Usually drawn when a clot is suspected; no fasting is required.
When to talk to a doctor
Seek urgent care for leg swelling/pain or sudden breathlessness; D-dimer is interpreted by a doctor in context.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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