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.
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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.
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.
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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 — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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