CRP (C-reactive protein)
C-reactive protein (CRP) is a protein the liver makes in response to inflammation. It rises quickly and falls quickly.
At a glance
- Sample
- Blood
- Units
- mg/L (most labs), mg/dL (some US labs)
- Preparation
- No special preparation is usually needed. If other tests are done from the same sample, you may be asked to come fasting.
Units: mg/dL and mg/L
Most labs print CRP in mg/L; some US labs print it in mg/dL, a number ten times smaller. High-sensitivity CRP (hs-CRP) uses the same units. To convert, multiply mg/dL by 10.
mg/L = mg/dL × 10
This converter changes units only. It doesn’t tell you whether a number is in or out of any range: that depends on the range printed by your own lab, and on your doctor. Soma does not diagnose and is not medical advice.
Why lab ranges differ
Each lab sets its reference range for its own method and analyser, and many ranges differ by age and sex. Two labs can print different ranges for the same blood, so a result is read against the range on its own report, not against a number from another lab or a website.
Soma charts every CRP result against the range printed by the lab that measured it.
What can affect the result
- A recent cold or vaccination.
- Hard exercise the day before.
- A fresh injury or surgery.
If something like this applies, mention it to the doctor who reads your results.
Questions
How do I convert CRP from mg/dL to mg/L?
Multiply mg/dL by 10. For example, 0.5 mg/dL is 5 mg/L.
Why does my lab’s CRP range differ from another lab’s?
Each lab sets its range for its own method and equipment, and many ranges differ by age and sex. That’s why a result is best read against the range printed on the same report.
How do I prepare for a CRP test?
No special preparation is usually needed. If other tests are done from the same sample, you may be asked to come fasting. Follow your lab’s instructions.
Related tests
Got a lab report with CRP?
Share it to Soma: it reads every row on your phone, with no account and no upload, and puts your CRP on one chart with your earlier results, each against the range your lab printed.
Sources
- C-Reactive Protein (CRP) Test — MedlinePlus, U.S. National Library of Medicine.
- Units: 1 mg/dL = 10 mg/L by the metric prefixes, as the Soma app converts.
Mention of a source doesn’t mean it endorses Soma. This page explains the test; it doesn’t diagnose and is not medical advice. Talk to your doctor about what your results mean.