Fibrinogen Antigen
Measures the amount of fibrinogen protein, the clotting factor your body turns into fibrin to form clots.
Consider this test if:
- Working up unexplained bleeding, easy bruising, or a prolonged clotting time
- Investigating a suspected inherited fibrinogen deficiency or dysfibrinogenemia, especially with a family history
- Sorting out abnormal coagulation results during illness, liver disease, or suspected DIC
- Tracking fibrinogen during or after clot-dissolving (thrombolytic) therapy
- Pairing antigen with a fibrinogen activity test to tell a quantity problem from a function problem
- HSA/FSA eligible
- Typical results in 3-5 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. Fibrinogen rises with inflammation, acute illness, infection, pregnancy, and estrogen-containing medications, so note any of these, since they can lift the result above your baseline. The sample is citrated plasma that must be processed and frozen promptly, so collection follows a specific tube and handling protocol at the draw site.
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What this test is for
Fibrinogen (Factor I) is a protein made by the liver and converted into fibrin, the mesh that holds a blood clot together. This antigen test measures how much fibrinogen protein is physically present, which is the key distinction from a fibrinogen activity test: antigen counts the molecules, activity measures whether they clot properly. Comparing the two is how dysfibrinogenemia is identified, where the protein level is normal or near-normal but the protein does not work, while a low antigen level points to inherited or acquired fibrinogen deficiency. Low fibrinogen is also seen in disseminated intravascular coagulation and advanced liver disease, and antigen levels are used to follow the effect of thrombolytic (clot-dissolving) therapy. Because fibrinogen is an acute-phase reactant, levels rise with inflammation, infection, pregnancy, and estrogen use.
- Specimen
- Platelet-poor plasma
- Method
- Nephelometry
- Measures
- Mass concentration
What you'll learn
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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.
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Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
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Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
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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 3-5 days
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
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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.
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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.
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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.
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$9 /mo
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Without membership
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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. 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.
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