Fibrinogen levels: what's normal, high and low
A clotting protein. Also rises with inflammation as an acute-phase reactant.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
Fibrinogen is measured with a standard blood draw; no fasting is needed. A typical reference range is 200 – 400 mg/dL. At TestWell it's $22.99 all-in as Fibrinogen Activity, results in 2–4 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- mg/dL
- Sample
- Blood draw
- Fasting
- Not required
- Results
- 2–4 business days
- Price
- $22.99
- Labs
- Quest or Labcorp · BioReference in NY/NJ
Fibrinogen Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 200 – 400 mg/dL |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
Have a result in hand? analyze it with your AI assistant using these reviewed ranges, or run it through our explainer. Tools: look up another marker's range · convert lab units
What your Fibrinogen result may mean
Often reflects inflammation, infection, or pregnancy.
What a high Fibrinogen means: causes, symptoms, next steps ↓Can reflect liver disease, severe bleeding, or rare genetic factor deficiency.
What a low Fibrinogen means: causes, symptoms, next steps ↓Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
What does a high Fibrinogen mean?
Fibrinogen is both a clotting factor and an acute-phase protein, so a high level most often reflects inflammation, infection, recent surgery or injury, pregnancy, smoking, obesity or oral estrogens. Persistently high fibrinogen is associated with higher cardiovascular risk, which is why it appears on heart-health panels — though it is a risk marker, not a target to treat directly.
Common causes of a high Fibrinogen
- Acute or chronic inflammation, infection
- Pregnancy, oral contraceptives or estrogen therapy
- Smoking, obesity, sedentary lifestyle, older age
- Recent surgery, trauma, heart attack, stroke
- Cancer, nephrotic syndrome, diabetes
Ordered from most to least common.
Symptoms that can go with it
- None from fibrinogen itself
What clinicians usually check next
- hs-CRP to confirm inflammation; repeat when well
- Cardiovascular risk review — lipids, ApoB, blood pressure, A1c
- Lifestyle factors (smoking cessation, activity, weight) are what lower it
Follow-up tests at TestWell: Heart & Body Inflammation Test (hs-CRP) ($34.99), C-Reactive Protein (CRP) ($26.99).
Does high fibrinogen mean I'm at risk of a clot?
Modestly — it is one of several markers associated with cardiovascular and clot risk, alongside smoking, lipids, blood pressure and glucose. It is not a reason for blood thinners by itself.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
What does a low Fibrinogen mean?
Low fibrinogen means either the liver is making less (advanced liver disease, malnutrition) or it is being consumed faster than it can be made — disseminated intravascular coagulation in sepsis or severe illness, major bleeding, or after thrombolytic drugs. Rare inherited deficiencies exist. A low fibrinogen raises bleeding risk and, below about 100 mg/dL, is a finding to act on the same day.
Common causes of a low Fibrinogen
- Advanced liver disease, cirrhosis
- Disseminated intravascular coagulation (sepsis, trauma, obstetric emergencies, some leukemias)
- Massive bleeding or transfusion, thrombolytic therapy
- Malnutrition, L-asparaginase chemotherapy
- Inherited afibrinogenemia or dysfibrinogenemia (rare)
Ordered from most to least common.
Symptoms that can go with it
- Easy bruising, prolonged bleeding, nosebleeds
- Often none when mildly low
What clinicians usually check next
- PT/INR, aPTT, platelet count, D-dimer, liver panel
- Hematology review for persistent unexplained low values
Follow-up tests at TestWell: Platelet Count ($14.99), PT and PTT (Prothrombin & Partial Thromboplastin Time) ($26.99), D-Dimer ($69.99).
Seek care promptly if
- Fibrinogen under ~100 mg/dL, or any low value with active bleeding — emergency care
Can fibrinogen be low in a healthy person?
Mild lows occasionally appear in slim, very fit people and some inherited variants without symptoms. Anything under 150 mg/dL, or a drop from a previous result, should be repeated and explained.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
How do you get a Fibrinogen test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. Fibrinogen is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Fibrinogen Activity | This marker only | $22.99 |
| Inflammation Panel | 7 tests | $119.99 |
| Blood Clotting Panel | 4 tests | $149.99 |
| Total Body Essentials Panel | 39 tests | $399.99 |
| Total Body Panel | 49 tests | $599.99 |
Quest vs. Labcorp for Fibrinogen: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $22.99 |
| Labcorp | Yes | $22.99 |
| BioReference (NY & NJ) | Yes | $30.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Frequently asked
What does a high Fibrinogen mean?
Fibrinogen is both a clotting factor and an acute-phase protein, so a high level most often reflects inflammation, infection, recent surgery or injury, pregnancy, smoking, obesity or oral estrogens. Persistently high fibrinogen is associated with higher cardiovascular risk, which is why it appears on heart-health panels — though it is a risk marker, not a target to treat directly.
Does high fibrinogen mean I'm at risk of a clot?
Modestly — it is one of several markers associated with cardiovascular and clot risk, alongside smoking, lipids, blood pressure and glucose. It is not a reason for blood thinners by itself.
What does a low Fibrinogen mean?
Low fibrinogen means either the liver is making less (advanced liver disease, malnutrition) or it is being consumed faster than it can be made — disseminated intravascular coagulation in sepsis or severe illness, major bleeding, or after thrombolytic drugs. Rare inherited deficiencies exist. A low fibrinogen raises bleeding risk and, below about 100 mg/dL, is a finding to act on the same day.
Can fibrinogen be low in a healthy person?
Mild lows occasionally appear in slim, very fit people and some inherited variants without symptoms. Anything under 150 mg/dL, or a drop from a previous result, should be repeated and explained.
Do I need a doctor's order to test my fibrinogen?
No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.
How long does it take to get Fibrinogen results?
Most Fibrinogen results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal.
How much does a Fibrinogen test cost?
Our Fibrinogen Activity starts at $22.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted.
Do I need to fast before my Fibrinogen test?
Fasting is not required for the Fibrinogen test. You can have your blood drawn any time of day.
Which lab will process my Fibrinogen test?
Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations.
What can throw off a Fibrinogen result?
Smoking and nicotine can change a Fibrinogen result without anything being wrong. Smoking and nicotine can raise Fibrinogen — do not attribute a mildly high CRP to another cause without considering smoking. Each is explained on our physician-reviewed "Before your test" pages; when one applies, remove it and retest.
Ready to test your fibrinogen?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $22.99.