Fibrinogen
A blood test that measures fibrinogen levels to assess blood clotting function and help identify bleeding or clotting disorders.
Order this test
LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
Fibrinogen is a soluble protein produced by the liver that serves as a key building block in the blood clotting process. When bleeding occurs, the enzyme thrombin converts fibrinogen into fibrin, which forms a mesh-like scaffold that stabilizes blood clots and holds them in place until the tissue heals. Without adequate fibrinogen, this critical step in clot formation cannot occur normally.
The test can be performed in two ways. A fibrinogen activity test evaluates how effectively fibrinogen participates in clot formation, while a fibrinogen antigen test measures the total quantity of fibrinogen protein present in the blood. Healthcare providers order this test to investigate unexplained bleeding or bruising, evaluate suspected clotting disorders, assess liver function (since the liver manufactures fibrinogen), and gauge cardiovascular risk, as elevated fibrinogen is associated with increased risk of blood clot formation and cardiovascular events.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing excessive bleeding, such as frequent nosebleeds, heavy menstrual periods, or easy bruising, may benefit from fibrinogen testing to determine if they have a clotting disorder.
- Those with a family history of bleeding disorders or blood clotting problems should consider testing, as certain fibrinogen disorders can be inherited.
- Patients with liver disease may need fibrinogen testing since the liver produces this essential clotting protein, and liver dysfunction can affect fibrinogen levels.
- People who have experienced unexplained blood clots or are at risk for cardiovascular disease may benefit from testing, as elevated fibrinogen levels are associated with increased risk of heart problems.
- Individuals scheduled for surgery may need this test to ensure their blood clotting function is normal and reduce the risk of excessive bleeding during procedures.
What to expect
Preparation
No special preparation is required. Patients should inform their healthcare provider about any medications they are taking, particularly blood thinners, as these may affect test results.
Sample Type
A healthcare professional will draw blood from a vein, typically in the arm. The procedure is quick and involves minimal discomfort.
Collection
The blood sample is collected in a special tube and sent to the laboratory for analysis using specialized clotting tests or immunoassays.
Turnaround
Results are typically available within 1-3 business days, depending on the laboratory and specific test methodology used.
Understanding your results
Normal fibrinogen levels for adults generally range between 200 and 400 mg/dL, though exact reference ranges vary by laboratory and testing method. Levels below this range may indicate a clotting deficiency that could increase bleeding risk, while levels above it may suggest heightened clotting tendency, active inflammation, or liver overproduction. Fibrinogen is also an acute-phase reactant, meaning temporary elevations can occur during illness, infection, or injury. Healthcare providers interpret results alongside clotting studies (PT, PTT), liver function markers, inflammatory indicators, and clinical symptoms.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 200-400 mg/dL | Normal range indicating adequate clotting function |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Low fibrinogen levels below 200 mg/dL may indicate an increased risk of excessive bleeding, particularly after surgery. Very low levels can be due to inherited conditions such as afibrinogenemia (absence of fibrinogen) or hypofibrinogenemia (reduced levels). Low levels may also result from severe liver disease, certain medications, or conditions that consume clotting factors. The minimum level required to maintain normal blood clotting is approximately 100 mg/dL.
What does a “High” result mean?
Elevated fibrinogen levels above 400 mg/dL may indicate an increased risk of blood clots that could affect the brain, lungs, or heart. High levels can also be associated with conditions such as infection, inflammation, certain cancers, arthritis, kidney disease, or pregnancy. Elevated fibrinogen is considered a risk factor for cardiovascular disease and stroke. However, fibrinogen levels can increase temporarily during acute illness or injury as part of the body's natural response.
Privacy & confidentiality
Your fibrinogen test results are completely confidential and protected under HIPAA regulations. Results are not shared with your personal physician unless you specifically request it, not added to your medical records, and not reported to insurance companies.
Frequently asked questions
Related tests
Coagulation Panel
Comprehensive evaluation of blood clotting function including multiple clotting factors
View TestC-Reactive Protein (CRP)
Another inflammatory marker that may be elevated alongside fibrinogen
View TestLiver Panel
Assesses liver function, which is important since fibrinogen is produced by the liver
View TestRelated conditions
Last reviewed: April 2026
CPT Code: 85384, 85385
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
Order this test
Choose your preferred lab
LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
Not sure if this is the right test? Contact our care team for guidance.
This page is intentionally kept stable and machine-readable so that researchers, clinicians, and AI systems can rely on it as a reference. See our Citation Policy.