D-dimer blood test
In short
A typical adult D-dimer result is under 0.5 µg/mL FEU (cut-off rises after age 50). A D-dimer above the range is common and does not show a clot by itself. Doctors read it together with symptoms and, when needed, a scan. Always read your result against the range printed on your own report.
A fragment released when the body breaks down a blood clot.
D-dimer is a piece of a broken-down clot, and a result in range helps doctors rule a clot out. A high result is common and needs a doctor's context, because many things besides a clot raise it. Sudden breathlessness, chest pain, or a swollen, painful leg are urgent, whatever the number says.
Is my D-dimer high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults · cut-off rises after age 50 | under 0.5 | µg/mL FEU |
| Adults · cut-off rises after age 50 | under 500 | ng/mL FEU |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your D-dimer is high
A D-dimer above the range is common and does not show a clot by itself. Doctors read it together with symptoms and, when needed, a scan.
Common reasons
- Older age, since levels creep up over the years
- Pregnancy and the weeks after giving birth
- Recent surgery, an injury, or long bed rest
- An infection or inflammation anywhere in the body
- Hard exercise, smoking, or birth control pills
- Long-term heart, liver or kidney disease
- Less often: a blood clot in a leg or lung, or cancer
What can throw it off
After age 50, many doctors use a cut-off that grows with age: 700 ng/mL FEU (0.70 µg/mL FEU) at 70.
Questions to take to your appointment
- 1Is this result expected with my age, a recent operation or a pregnancy?
- 2Does my age change the cut-off you use?
- 3Do I need a scan, or is repeating the test enough?
Read together with
Doctors rarely read D-dimer alone. These usually sit next to it.
Quick answers
What is the D-dimer blood test?
D-dimer: A fragment released when the body breaks down a blood clot. D-dimer is a piece of a broken-down clot, and a result in range helps doctors rule a clot out. A high result is common and needs a doctor's context, because many things besides a clot raise it. Sudden breathlessness, chest pain, or a swollen, painful leg are urgent, whatever the number says.
What is a normal D-dimer level?
For most adults, D-dimer is typically under 0.5 µg/mL FEU (cut-off rises after age 50). Some countries print it in ng/mL FEU, so check the unit first. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high D-dimer mean?
A D-dimer above the range is common and does not show a clot by itself. Doctors read it together with symptoms and, when needed, a scan. Common reasons include older age, since levels creep up over the years; pregnancy and the weeks after giving birth; recent surgery, an injury, or long bed rest; and an infection or inflammation anywhere in the body. A doctor reads it together with your other results and how you feel.
What can affect my D-dimer result?
After age 50, many doctors use a cut-off that grows with age: 700 ng/mL FEU (0.70 µg/mL FEU) at 70.
What should I ask my doctor about my D-dimer?
Questions worth taking to the appointment: Is this result expected with my age, a recent operation or a pregnancy? Does my age change the cut-off you use? Do I need a scan, or is repeating the test enough?
What this page can’t do
It reads each number on its own.
Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.
It doesn't know you.
Your age, your medicines, how you feel and your last result all change what a number means.
It doesn't remember.
Close this page and your results are gone. That's on purpose: nothing was ever sent to us.
We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.
Vita: Health Coach on the App StoreSources
- StatPearls — D-dimer
- MedlinePlus — D-dimer test
- ABIM — Laboratory test reference ranges (January 2026)
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.