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Fibrinogen in two units: the short answer
To convert fibrinogen from mg/dL to g/L, multiply by 0.01. To go back from g/L to mg/dL, multiply by 100 (or divide by 0.01). For example, 300 mg/dL × 0.01 = 3.00 g/L. The converter above works in both directions and shows where the result sits against typical reference ranges.
What the test measures
Fibrinogen (clotting factor I) is reported in mg/dL in the US and g/L in the UK, Europe and Australia. It's a pure scaling conversion: 1 mg/dL = 0.01 g/L, so 300 mg/dL = 3.0 g/L.
Why the units differ
Bleeding and transfusion guidance in surgery, trauma and obstetrics often uses g/L thresholds such as 1.5 g/L or 2 g/L, so US values in mg/dL need converting.
Where the factor comes from
The conversion factor comes from the molar mass (n/a (mass units)) and the volume units on each side. Laboratories may round the factor slightly differently, which can change the last digit but never the clinical meaning.
How to convert step by step
- Check the unit printed next to the result on your report – mg/dL or g/L.
- mg/dL → g/L: multiply by 0.01.
- g/L → mg/dL: multiply by 100.
- Round to the same number of decimals your lab uses.
Worked example in reverse: 1.5 g/L × 100 = 150.0 mg/dL.
Fibrinogen conversion chart
| mg/dL | g/L |
|---|---|
| 50 | 0.5 |
| 100 | 1 |
| 150 | 1.5 |
| 200 | 2 |
| 250 | 2.5 |
| 300 | 3 |
| 350 | 3.5 |
| 400 | 4 |
| 500 | 5 |
| 700 | 7 |
| g/L | mg/dL |
|---|---|
| 0.5 | 50 |
| 1 | 100 |
| 1.5 | 150 |
| 2 | 200 |
| 2.5 | 250 |
| 3 | 300 |
| 3.5 | 350 |
| 4 | 400 |
| 5 | 500 |
| 7 | 700 |
Fibrinogen levels: what the numbers mean
| Category | mg/dL | g/L |
|---|---|---|
| Low<1.5 g/L – increased bleeding risk in surgery, trauma or obstetric haemorrhage | < 150 | < 1.5 |
| Typical adult range2.0–4.0 g/L; varies by lab | 200 – 400 | 2 – 4 |
Typical Clauss fibrinogen reference interval. Fibrinogen rises in pregnancy and inflammation.
Typical Clauss fibrinogen reference interval. Fibrinogen rises in pregnancy and inflammation.
Interpreting fibrinogen results
Fibrinogen is turned into fibrin to form the mesh of a blood clot. Low levels come from heavy bleeding with replacement fluids, disseminated intravascular coagulation, severe liver disease or rare inherited deficiencies. High levels are common and non-specific, rising with inflammation, pregnancy and smoking; large studies link persistently high fibrinogen with cardiovascular risk, but it is not used as a routine screening test.
A single result outside the reference range is common and often not significant on its own. Reference ranges are set so that about 1 in 20 healthy people fall outside them, and every laboratory sets its own limits for its method. Use the range printed on your report and discuss results with the clinician who ordered the test.
When to see a doctor
Contact your clinician if a result is flagged as abnormal and you have symptoms, if a value is far outside the range, or if results are changing over time. This page explains units; it cannot diagnose or replace medical advice.
Frequently asked questions
What is 2 g/L fibrinogen in mg/dL?
2 × 100 = 200 mg/dL.
Why is my fibrinogen high?
Fibrinogen is an acute-phase protein, so infection, inflammation, pregnancy, smoking and older age all raise it.
Can I use this converter for any lab?
Yes for the unit conversion, which is fixed by chemistry. Reference ranges differ between labs and methods, so compare your converted value with your own lab's range.