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D-dimer, Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of D-dimer, a protein fragment produced when blood clots dissolve. It helps assess whether you may have a blood clot or increased risk of clot-related complications.

Quick summary

["D-dimer helps diagnose or rule out blood clots and assess clot risk."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
3247-4
Short code
Deprecated D Dimer PPP Ql LA
Synonyms
Deprecated D Dimer PPP Ql LA
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a D-dimer test to investigate symptoms like unexplained bruising, swelling, or shortness of breath that could suggest a blood clot. It may also be used to evaluate conditions like deep vein thrombosis (DVT), pulmonary embolism, or other clotting disorders. Sometimes, it’s part of a broader evaluation for conditions like cancer or inflammation.

What to Expect Before the Test

No special preparation is usually needed. You may have blood drawn from a vein in your arm. If you’re taking blood thinners, let your provider know—this can affect results.

What Does the Test Result Mean?

A high D-dimer level often indicates recent clot formation or increased risk. A low or normal level suggests no significant clotting activity. However, a normal result doesn’t always rule out a clot, especially in certain conditions. Your provider will interpret results in the context of your symptoms and medical history.

Possible Risks or Side Effects

The most common side effect is mild pain or bruising at the needle site. Rarely, there may be a slight swelling or redness. If you experience excessive bleeding or signs of infection (like fever or increased pain), contact your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

D-dimer

Frequently asked questions

What does a high D-dimer level mean?
A high D-dimer level strongly suggests recent clot formation or a higher risk of clotting, which may require further testing or treatment (e.g., blood thinners). However, it can also be elevated in other conditions like pregnancy, severe infection, or cancer, so results must be reviewed carefully.
Why might my D-dimer be normal when I have symptoms of a clot?
A normal D-dimer level doesn’t always confirm the absence of a clot, especially if symptoms are mild or if the clot is in a hard-to-detect location (e.g., pulmonary embolism). Additional imaging tests or other blood tests may be needed for confirmation.
Can D-dimer levels change over time?
Yes, D-dimer levels can fluctuate depending on whether you’re forming or dissolving clots, your overall health, and certain medications (like blood thinners). Your provider will track changes over time as part of your care plan.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy