How to Convert CRP mg/L to mg/dL
C-reactive protein is reported in mg/L in most of the world and sometimes in mg/dL in the US. Because both are mass-per-volume units, the conversion is a simple factor of 10 — no molecular weight involved.
CRP mg/dL = CRP mg/L ÷ 10 CRP mg/L = CRP mg/dL × 10 CRP mg/L to mg/dL Chart
| mg/L | mg/dL | Context |
|---|---|---|
| 1 mg/L | 0.1 mg/dL | hs-CRP low risk |
| 3 mg/L | 0.3 mg/dL | hs-CRP high-risk threshold |
| 10 mg/L | 1.0 mg/dL | Upper normal / inflammation begins |
| 50 mg/L | 5.0 mg/dL | Moderate elevation |
| 100 mg/L | 10.0 mg/dL | Marked elevation |
| 200 mg/L | 20.0 mg/dL | Severe (often bacterial) |
mg/dL to mg/L Reverse Chart
| mg/dL | mg/L |
|---|---|
| 0.3 mg/dL | 3 mg/L |
| 1.0 mg/dL | 10 mg/L |
| 5.0 mg/dL | 50 mg/L |
| 10.0 mg/dL | 100 mg/L |
hs-CRP and Cardiovascular Risk
High-sensitivity CRP (hs-CRP) is used to help gauge cardiovascular risk. The American Heart Association categories are defined in mg/L — this is the number that matters here:
| Category | mg/L | mg/dL |
|---|---|---|
| Low cardiovascular risk | Below 1 mg/L | Below 0.1 mg/dL |
| Average risk | 1 – 3 mg/L | 0.1 – 0.3 mg/dL |
| High risk | Above 3 mg/L | Above 0.3 mg/dL |
Because these cut-offs are small, they are always reported in mg/L — converting to mg/dL gives 0.1 and 0.3 mg/dL, which are easy to misread. A very high hs-CRP is usually rechecked, since a recent infection can raise it temporarily.
Standard CRP: Inflammation and Infection
Standard (not high-sensitivity) CRP is used for infection and inflammation:
| Category | mg/L | mg/dL |
|---|---|---|
| Normal | Below 10 mg/L | Below 1.0 mg/dL |
| Mild elevation | 10 – 40 mg/L | 1.0 – 4.0 mg/dL |
| Moderate (active inflammation) | 40 – 200 mg/L | 4.0 – 20 mg/dL |
| Marked (severe infection) | Above 200 mg/L | Above 20 mg/dL |
Standard CRP assays measure roughly 10–1,000 mg/L, while hs-CRP measures the low end (about 0.5–10 mg/L) more precisely — which is why the two tests are ordered for different questions.
Worked Example
Suppose a report shows 45 mg/L and you want mg/dL:
45 ÷ 10 = 4.5 mg/dL 45 mg/L is a moderate elevation, suggesting active inflammation. Converting back, a 0.3 mg/dL hs-CRP is 3 mg/L — the high-risk threshold.
Frequently Asked Questions
How do you convert CRP mg/L to mg/dL?
Divide mg/L by 10. For example, 30 mg/L is 3.0 mg/dL.
What is a normal CRP?
Below about 10 mg/L (1.0 mg/dL) for standard CRP.
What is the difference between CRP and hs-CRP?
Same protein; hs-CRP measures low levels for cardiac risk, standard CRP for infection.
What are the hs-CRP risk bands?
<1 low, 1–3 average, >3 high (mg/L).
References
- Medscape — C-Reactive Protein: Reference Range and Interpretation.
- American Heart Association hs-CRP cardiovascular risk categories (<1, 1–3, >3 mg/L); CRP mg/dL × 10 = mg/L.
Conclusion
Converting CRP between mg/L and mg/dL is a simple ÷10. The key is which test you have: hs-CRP with its 1 and 3 mg/L cardiovascular thresholds, or standard CRP for infection and inflammation. Interpret the result with your healthcare provider.