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D-dimer (Plasma) – Fibrin Degradation Products

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

This test measures small protein fragments produced when blood clots break down, helping assess risk of blood clots or clot-related conditions.

Quick summary

["D-dimer helps diagnose or monitor conditions tied to abnormal clotting."]

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

Key facts at a glance

LOINC
12277-0
Short code
dsDNA Ab Ser Ql Farr
Synonyms
dsDNA Ab Ser Ql Farr
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
farr
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 This Test Is Done

Your doctor may order a D-dimer test to check for signs of blood clots (thrombosis) or conditions like deep vein thrombosis (DVT) or pulmonary embolism. It’s also used to evaluate patients with unexplained bleeding or after a stroke to rule out clotting issues.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. The process takes about 5 minutes. If you’re on blood thinners, let your doctor know before testing.

What the Results Mean

High levels of D-dimer often suggest recent blood clotting activity. Very low or absent levels may indicate no active clotting or bleeding disorders. Results alone aren’t diagnostic—they’re usually interpreted alongside other tests and symptoms.

Common Conditions Monitored

D-dimer is used to diagnose or rule out conditions like DVT, pulmonary embolism, or arterial thrombosis. It’s also sometimes checked in patients with unexplained fatigue, chest pain, or symptoms of stroke.

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 mean?
A high D-dimer result may indicate recent clot formation, but it doesn’t confirm a clot alone. Your doctor will consider your symptoms, medical history, and other tests (like imaging) to make a full diagnosis.
Can D-dimer be used to monitor treatment?
Yes, in some cases, D-dimer levels can help track how well blood thinners are working or if a clot is resolving. However, it’s not always used for routine monitoring and depends on the specific condition.
Is D-dimer the same as a clot test?
Not exactly. While D-dimer is closely tied to clotting activity, it’s a marker of clot breakdown. Other tests (like PT/INR or aCTT) measure clotting function directly, while imaging (like CT scans) confirms clot presence.
  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