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D-dimer (Serum/Plasma Mass Concentration)

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

This test measures the level of D-dimer, a protein fragment produced when blood clots break down. It helps assess whether you may have a condition involving abnormal clotting or clot breakdown.

Quick summary

["D-dimer helps detect potential blood clots or conditions like deep vein thrombosis or pulmonary embolism."]

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

Key facts at a glance

LOINC
63222-4
Short code
dsDNA Ab Plr IA-aCnc
Synonyms
dsDNA Ab Plr IA-aCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is D-Dimer Used For?

D-dimer is primarily used to evaluate suspected blood clots (thrombosis) or conditions where clots may form, such as deep vein thrombosis (DVT) or pulmonary embolism (PE). It can also support the diagnosis of other clotting disorders or help rule out certain bleeding risks.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The blood is then processed to measure D-dimer levels. The test is quick and typically done in a lab setting.

What Might Affect Results?

Several factors can influence D-dimer levels, including recent blood clots, pregnancy, certain medications (like anticoagulants), infections, or severe illness. Smoking or recent trauma may also temporarily affect results.

When Might You Need This Test?

Your doctor may order a D-dimer test if you have symptoms like leg swelling, chest pain, shortness of breath, or if you’ve been diagnosed with a condition that increases clot risk, such as atrial fibrillation or cancer.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: D-dimer plays a key role in diagnosing or ruling out blood clots. High levels suggest recent clot activity, while very low levels may indicate no active clotting process. However, it’s not definitive on its own and is often used alongside other tests or imaging.

Short name

D-Dimer

Frequently asked questions

Why might my doctor want to check my D-dimer level?
Your doctor may recommend this test to investigate symptoms like unexplained leg swelling, chest pain, or shortness of breath, or to assess risks for blood clots in conditions like cancer, pregnancy, or heart disease.
What do my D-dimer results mean?
Results can vary widely and depend on your overall health and medical history. High levels often point to recent clot activity, but your doctor will consider other factors to guide further testing or treatment.
Can I prepare for this test?
No special preparation is needed, but avoid heavy meals or strenuous activity before the blood draw. If you’re on blood thinners, let your doctor know before the test.
  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