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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 breakdown product of clotting factors that forms when blood clots dissolve. It helps assess whether abnormal clotting or clot breakdown is occurring in your body.

Quick summary

["D-dimer helps diagnose or monitor blood clotting disorders."]

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

Key facts at a glance

LOINC
15177-9
Short code
dsDNA Ab Fld-aCnc
Synonyms
dsDNA Ab Fld-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What Is D-Dimer Used For?

D-dimer is primarily used to evaluate conditions involving abnormal blood clotting or clot breakdown, such as deep vein thrombosis (blood clots in veins) or pulmonary embolism (clots in the lungs). It may also be used in certain cancer-related blood clotting risks or after trauma.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed using a specialized immunoassay or turbidimetric method to detect D-dimer levels.

Why Might Your Doctor Order This Test?

Your doctor may order a D-dimer test if you have symptoms of blood clots (e.g., swelling, pain, shortness of breath) or if you have risk factors like recent surgery, pregnancy, or a history of clotting disorders. It can also help rule out certain conditions or guide treatment decisions.

What Are Common Results and Interpretation?

Results are not given in absolute numbers but are compared to a reference range for your lab. High levels of D-dimer often suggest recent clot formation or clot breakdown, while low or normal levels may indicate no active clotting disorder.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: D-Dimer plays a key role in diagnosing suspected blood clots. Elevated levels can confirm a diagnosis in many cases, while low levels may help exclude clotting disorders. However, it is not definitive on its own and is often used alongside other tests or clinical findings.

Short name

D-Dimer

Frequently asked questions

What does a high D-dimer level mean?
A high D-dimer level may indicate recent clot formation or clot breakdown, such as in deep vein thrombosis, pulmonary embolism, or other conditions involving abnormal clotting. Your doctor will consider the results alongside your symptoms and other tests to make a diagnosis.
Can D-dimer levels change over time?
Yes, D-dimer levels can change depending on whether you are experiencing active clot formation or breakdown. For example, levels may rise after a clot forms and then begin to decrease as the body dissolves it. Your doctor may retest if needed to monitor changes.
Is there anything I should avoid before the test?
Avoid strenuous exercise or activities that may increase blood clotting risk 24 hours before the test. Follow any specific instructions your healthcare provider gives you, such as fasting or avoiding certain medications, if applicable.
  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