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Fibrinogen Test

⚠️ Update approaching🔬 Evidence: ModerateHematology
Diğer adları: Factor I, Fibrinogen level, Fibrinogen test
⚠️

Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• The key clotting protein (Factor I) involved in clot formation • Also an acute phase reactant — rises with inflammation • Normal: approximately 200–400 mg/dL • Critical low: <100 mg/dL — serious bleeding risk

🧪 What Does This Test Measure?

The fibrinogen test measures the level of fibrinogen (Factor I), the key clotting protein that forms the structural framework of blood clots and also rises as an acute phase reactant.

📋 Why Is It Ordered?

Ordered for bleeding disorder evaluation, DIC investigation, and preoperative clotting assessment.

🔧 Preparation

Fasting is generally not required. Blood is collected in a citrated tube. Result turnaround time may vary.

📊 Reference Ranges

Normal: approximately 200–400 mg/dL (2.0–4.0 g/L) Critical low: <100 mg/dL — serious bleeding risk ⚠️ Reference ranges vary by laboratory.

⬆️ High Values

Elevated fibrinogen may be associated with inflammation, infection, pregnancy, smoking, or obesity. It is an acute phase reactant.

⬇️ Low Values

Low fibrinogen may be associated with DIC, advanced liver disease, massive bleeding, thrombolytic therapy, or rare inherited deficiencies.

⚙️ What Can Affect Results?

Inflammation, pregnancy, liver function, medications, assay method, and smoking may affect fibrinogen results.

🔬 Evidence Summary

Moderate evidence: 2 guidelines and 2 reviews.

📚 Most Important Studies on This Topic

1

International council for standardisation in haematology recommendations on fibrinogen assays, thrombin clotting time and related tests in the investigation of bleeding disorders

Guideline· International Journal of Laboratory Hematology · 2024 · PMID: 37984807

2

Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation

Guideline· Thrombosis and Haemostasis · 2001 · PMID: 11816725

3

Fibrinogen: Structure, abnormalities and laboratory assays

Review· Advances in Clinical Chemistry · 2024 · PMID: 38762239

✅ Key Takeaways

💡

What you learned: Fibrinogen is essential for clot formation and also rises with inflammation. Very low levels indicate serious bleeding risk.

⛔

A fibrinogen result alone cannot diagnose a clotting or bleeding disorder. Clinical context and additional tests are needed.

🔬 Sources Used on This Page

4 sources · Most recent publication: 2024
📋
Guideline
Expert society and guideline recommendations
2
sources
📖
Review
Comprehensive topic evaluation
2
sources
Overall assessment: Evidence level for this topic is moderate. This page is supported by 2 guidelines, 2 reviews.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

📋 References

[PMID: 37984807] International council for standardisation in haematology recommendations on fibrinogen assays, thrombin clotting time and related tests in the investigation of bleeding disorders. International Journal of Laboratory Hematology, 2024.
[PMID: 38762239] Fibrinogen: Structure, abnormalities and laboratory assays. Advances in Clinical Chemistry, 2024.
[PMID: 17605969] How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults. Mayo Clinic Proceedings, 2007.
[PMID: 11816725] Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thrombosis and Haemostasis, 2001.
Last reviewed: 4/2/2026
Next review: 4/2/2027

⚖️ Comparisons

D-Dimer vs Fibrinogen→

🔗 Related Topics

🧪 PT/INR (protrombin zamanı)🧪 aPTT (aktive parsiyel tromboplastin zamanı)🧪 D-dimer🧪 CRP (C-reaktif protein)🧪 Hemogram (trombosit sayısı)
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.