Fibrinogen
Fibrinogen is a liver-produced clotting factor and acute phase reactant that forms the fibrin mesh of blood clots. Elevated levels increase blood viscosity and thrombotic risk and are associated with cardiovascular events and chronic inflammation. Very low values can indicate liver failure, disseminated intravascular coagulation, or inherited fibrinogen disorders and raise bleeding risk.
Optimal range: who says what
Institutions, researchers and practitioners draw the line in different places. Each position is listed with who holds it and, where a document states it, a link. How we verify ranges.
- Institution or study200-300 mg/dLOptimizeBiomarkers editorial: lower half of the lab reference intervalLife Extension's 295-369 mg/dL sits mid-interval (Quest 175-425, Labcorp 209-464). The lower band follows the Fibrinogen Studies Collaboration (154,211 adults, 31 cohorts): long-term increases of 1 g/L (100 mg/dL) go with roughly double the risk of major cardiovascular events, though causality is uncertain.
- Named practitioner295-369 mg/dLLife Extension · Lab Testing Protocol (Suggested Optimal Ranges)Disclosure: Life Extension sells lab panels that appear in our blood-test comparisons.
- Lab reference interval200-400 mg/dLWhat a lab report flags against. A lab interval is not an optimal target.
Practitioner targets are individual positions, often tighter than guideline ranges. Each was checked against its article before publishing.
3 providers include this
Inflammation & Immune Markers
Why Fibrinogen matters
Essential for blood clot formation. Elevated levels increase blood viscosity and cardiovascular risk. Also an acute phase reactant elevated in chronic inflammation.
Which Providers Test Fibrinogen?
Function Health is both the cheapest ($365/year) and the most comprehensive (160+ biomarkers) panel that includes Fibrinogen.
3 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
 Function Health | $365 | 160+ | $2.28 |
| $700 | 138 | $5.07 | |
| $1950 | 130+ | $15.00 |
$/Biomarker is annual cost divided by the panel's advertised biomarker count, not the price of this one test. We track 23 blood test providers (32 plans); 21 of those plans are itemized marker by marker. Compare all of them.
18 itemized panels do not include Fibrinogen
Superpower · WHOOP Advanced Labs · Labcorp OnDemand · Life Extension Elite · Everlywell · Mito Health · InsideTracker · Marek Health Base · Marek Health Comprehensive · Marek Health Complete · Blueprint · Empirical Health · Oura Health Panels · SiPhox Health · Hims Labs · Healthspan · Vitality Blueprint Standard · Ultrahuman Blood Vision Annual
11 providers not itemized in our matrix
We have not itemized these marker by marker (some sell tests one at a time), so this page cannot say whether they offer Fibrinogen. Check with them directly.
Life Extension Standard · Quest Health · Ultrahuman Blood Vision · Lifeforce · Hundred Health · Personalabs · Walk-In Lab · HealthLabs · WHOOP Specialized Panels · Marek Health Essential · Vitality Blueprint Upload
Frequently Asked Questions
What is the optimal range for Fibrinogen?
Published position: 200-300 mg/dL (OptimizeBiomarkers editorial: lower half of the lab reference interval). Named practitioners target: 295-369 mg/dL (Life Extension). Lab reference interval: 200-400 mg/dL. That is what a lab report flags against, not an optimal target.
Which blood test providers include Fibrinogen?
3 of the 21 blood testing panels we itemize marker by marker include Fibrinogen in their panels. This biomarker has limited availability.
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Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed Sep 23, 2026 · First published Nov 30, 2025