Fibrinogen Activity
A clotting protein that flags bleeding risk when low and inflammation or cardiovascular risk when high.
Consider this test if:
- A personal or family history of easy bruising, prolonged bleeding after surgery, or unexplained bleeding
- Abnormal PT or aPTT results, or a workup for dysfibrinogenemia or DIC
- Known or suspected liver disease that can lower clotting protein production
- Tracking the effect of thrombolytic therapy on clotting
- Investigating an inflammatory or cardiovascular risk picture where fibrinogen adds context
- HSA/FSA eligible
- Typical results in 1 day · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. The sample is drawn into a 3.2% sodium citrate (light blue-top) tube and must be filled completely, since an underfilled tube skews the citrate-to-blood ratio and the result. Lipemia or hemolysis can interfere with the assay. High-dose heparin, direct thrombin inhibitors, and fibrin breakdown products can falsely lower the measured activity, so note any anticoagulant therapy. Recent infection, inflammation, pregnancy, or estrogen use can raise levels independent of any clotting disorder.
Video consult with your Care Team
A 1:1 call to discuss your health.
What members say on Trustpilot
What this test is for
Fibrinogen (factor I) is a liver-made protein that thrombin converts into fibrin, the mesh that holds a blood clot together. This test uses the Clauss method to measure functional fibrinogen activity, the working level of the protein rather than just its quantity. Low activity points to inherited deficiency (hypo- or afibrinogenemia), dysfibrinogenemia (a qualitatively defective protein), advanced liver disease, disseminated intravascular coagulation, or active thrombolytic therapy, and is worth checking in anyone with a bleeding tendency even when PT and aPTT look normal. High activity reflects an acute-phase response to infection, inflammation, tissue injury, autoimmune disease, or malignancy, and persistently elevated levels have been linked to atherosclerotic and prothrombotic cardiovascular risk. Because fibrinogen rises in pregnancy, with estrogen or oral contraceptives, and in smokers, and falls with heavy heparin or direct thrombin inhibitors, the result is read against your clinical context.
- Specimen
- Platelet-poor plasma
- Method
- Coagulation assay
- Measures
- Mass concentration
What you'll learn
-
Insights that connect the dots. A clinician reads your whole picture, not one result in isolation, connecting family history, past results, and lifestyle into clear next steps.
-
Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
-
Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
-
Never miss a recheck. Mito tells you what is worth retesting and when, then reminds you so nothing slips.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 1 day
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
-
Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
-
Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
-
Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
Mito Membership
$9 /mo
cancel anytime
Without membership
$0
pay as you go
At-cost pricing on labs, scans, and more
Supplements at 30% off retail prices Coming soon
On-demand clinician consults when you need guidance
Personalized action plans across supplements, exercise, nutrition, and sleep
AI health coaching to help you act on your results
Year-round medical support, with in-chat clinician escalation
All your health records in one personal vault, with trends and biological age tracking
Early access to new diagnostics and product releases
More tests to consider
Loading essentials…
Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost, covering the lab and what it takes to run the service. It is never a profit on the test itself. Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9 per month, and any applicable lab order or draw fee is itemized before you pay.
Where do I get tested?
Choose an available partner lab at checkout. If your cart contains multiple blood tests, Mito helps consolidate the eligible tests at one lab when possible. At-home kits and scans follow the collection or appointment process shown on their product page.
Is this eligible for HSA/FSA?
Yes. Eligible tests can be paid for with an HSA or FSA card at checkout.
When will I get my results?
Your results appear in your Mito dashboard after the laboratory completes processing. A clinician then reviews them before your analysis and personalized action plan are finalized. Timing varies by test, and specialty assays and at-home kits may take longer.
Do I need a physician's order?
No. Mito provides the laboratory order when one is required, so you do not need to arrange a separate physician visit before purchasing.
Recently viewed
Loading essentials…