Can this result diagnose a condition on its own?

No. Laboratory results are interpreted with symptoms, medical history, specimen conditions and related tests.

Which reference range should I use?

Start with the performing laboratory's own reference interval; clinical cutoffs, when relevant, are separate sourced thresholds used for a specific purpose.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, symptomatic or unexpected should be reviewed by a healthcare professional.

Information about a laboratory test

Fibrinogen: What Does This Test Measure?

The Fibrinogen test measures the level of fibrinogen, a clotting protein that is converted to fibrin during clot formation.

Test summary

Test name: Fibrinogen
Abbreviations: Fibrinogen, Factor I
Category: Coagulation / Acute Phase
Panel: Coagulation Assessment
Specimen: Citrated plasma
Common units: mg/dL, g/L

What does the test measure?

The Fibrinogen test measures the level of fibrinogen, a clotting protein that is converted to fibrin during clot formation.

Why is the test ordered?

It may be ordered to investigate abnormal bleeding or clotting, assess coagulation before procedures, or monitor selected anticoagulant therapies.

Information about a low result

Low fibrinogen can occur with consumption coagulopathy/DIC, severe liver disease, inherited fibrinogen disorders or major bleeding, among other causes.

Information about a high result

High fibrinogen can occur with inflammation, pregnancy and some cardiometabolic or thrombotic contexts; as an acute-phase protein it may be interpreted alongside inflammatory markers such as CRP.

Reference and clinical context

Start with the performing laboratory's reference interval, unit, specimen type and method. Numeric information on this page is stored as sourced example intervals or clinical thresholds.

Reference range 1

>= 200 – <= 400 mg/dL

Population: Adults / general laboratory example
Age range: 18
Specimen: Citrated plasma

Example adult fibrinogen reference interval

This is sourced reference/clinical-context information and should not be used alone as a diagnosis or treatment decision. The laboratory report, medication use and clinical context take priority.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Fibrinogen is both a clotting protein and an acute-phase reactant. D-dimer, PT/INR, aPTT, platelets and clinical context provide a more meaningful coagulation picture.

Related specialties

Hematology
Internal Medicine
Emergency Medicine

Frequently asked questions

More information about this test

Sources

C-Reactive Protein (CRP) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2025 · CRP testing, inflammation and nonspecific interpretation · Verified: Aug 12, 2026
Fibrinogen blood test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2025 · Fibrinogen purpose and example 200–400 mg/dL reference interval · Verified: Aug 12, 2026
D-Dimer Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · D-dimer use in clot assessment and non-thrombotic causes of elevation including pregnancy · Verified: Aug 12, 2026
Prothrombin Time Test and INR (PT/INR) — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · PT/INR purpose, anticoagulation and coagulation interpretation · Verified: Aug 12, 2026
Partial Thromboplastin Time (PTT) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · aPTT/PTT purpose, prolonged and shortened result context · Verified: Aug 12, 2026