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D-dimer (Substance Concentration) in Plasma

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 the risk of blood clots in your blood vessels.

Quick summary

["D-dimer helps doctors evaluate clot risks and guide treatment decisions."]

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

Key facts at a glance

LOINC
68389-6
Short code
dsDNA IgG Snv IA-aCnc
Synonyms
dsDNA IgG Snv 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
CPT
82784
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is D-dimer?

D-dimer is a marker created when blood clots dissolve naturally in your body. It’s not a standalone disease test but is often used alongside other tests to check for conditions like deep vein thrombosis (blood clots in veins) or pulmonary embolism (clots in the lungs).

Why Might You Need This Test?

Your doctor may order a D-dimer test if you have symptoms like swelling, pain in your legs, shortness of breath, or if you’ve been diagnosed with a condition that increases clot risk, such as atrial fibrillation or recent surgery. It’s also used to rule out clots in certain situations.

How Is the Test Done?

A blood sample is taken from a vein in your arm. The blood is sent to a lab, where it’s analyzed to measure D-dimer levels. The test typically takes a few hours to complete.

What Do the Results Mean?

Results are usually reported as a ratio or relative value compared to a standard. High levels may suggest recent clot formation, while very low levels may indicate no active clotting activity. Your doctor will interpret results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

D-dimer

Frequently asked questions

What are the possible causes of abnormal results?
Elevated D-dimer levels can be caused by conditions like deep vein thrombosis, pulmonary embolism, heart attack, or other clotting disorders. However, false positives can occur in conditions like pregnancy, cancer, or severe infections. Low levels are generally not clinically significant unless your doctor suspects a bleeding disorder.
How often should I get this test?
The frequency depends on your medical condition and treatment plan. Your doctor will determine how often you need retests based on your symptoms, risk factors, and test results from previous evaluations.
Can lifestyle changes affect D-dimer levels?
While lifestyle factors like smoking, obesity, or sedentary activity may influence clot risk, they don’t directly alter D-dimer levels. However, managing conditions like high blood pressure or diabetes can help reduce overall clot risk.
  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