- Made by
- The liver
- Reported in
- mg/L
- Heart-risk categories (CDC/AHA)
- Under 1 lower, 1–3 average, over 3 higher
- Risk-enhancing level (ACC/AHA 2019)
- 2.0 mg/L or above
Standard CRP versus high-sensitivity CRP
Both tests measure the same protein. A standard CRP test is built to spot the large jumps that come with infection, injury or flares of inflammatory disease. The high-sensitivity test reads much lower concentrations, which is what you need to detect the mild, chronic inflammation that plays a role in atherosclerosis.
How results are interpreted
A 2003 statement from the CDC and American Heart Association grouped hs-CRP into lower risk (below 1 mg/L), average risk (1 to 3 mg/L) and higher risk (above 3 mg/L). It recommended averaging two measurements taken about two weeks apart while you are well, and repeating any result above 10 mg/L after looking for an infection or other obvious cause.
The 2019 ACC/AHA prevention guideline lists an hs-CRP of 2.0 mg/L or higher as a "risk-enhancing factor." In practice, that means it can tip the balance for someone whose cholesterol-based risk is borderline or intermediate, for example when deciding about a statin.
What can throw it off
- A cold, flu, dental infection, injury or recent hard workout.
- Autoimmune or inflammatory conditions such as rheumatoid arthritis or inflammatory bowel disease.
- Smoking, obesity, poor sleep and depression.
- Oral menopausal hormone therapy; women also tend to run slightly higher.
- Some medicines and supplements, including NSAIDs.
Why it matters after 45
Heart disease risk climbs through midlife, and CRP tends to edge up with age too. hs-CRP is not a screening test for everyone; the CDC/AHA statement did not support testing the whole adult population. It earns its place when it might change a decision, and it should be read with cholesterol, ApoB, Lp(a), blood pressure and family history.
A low result does not prove you have no inflammation, and a high one does not tell you its source. If yours is elevated, a clinician will want to know how you felt on the day of the draw and may simply repeat it.
Preparing for an hs-CRP draw
Book the test for a week when you feel well, and avoid scheduling it the morning after an unusually intense training session. Mention any recent dental work, injuries or flare-ups of joint or bowel symptoms. If you take anti-inflammatory painkillers regularly, tell your clinician, since they can lower the reading. Comparing results from the same lab over time gives the clearest picture.
hs-CRP: common questions
Is hs-CRP the same as a CRP test?
They measure the same protein, but the high-sensitivity test is designed to detect much lower levels. Use the version your clinician orders for the question being asked.
Should I get tested if I just had a cold?
It is better to wait until you have fully recovered. Recent illness can raise the result and make it misleading.
Can lifestyle lower hs-CRP?
Weight loss, physical activity and not smoking are associated with lower levels in many people. Your clinician can track it over time if it is relevant to your risk.
Does a high hs-CRP mean I have heart disease?
No. It is one risk factor among many and is not a diagnostic test for heart disease.
Why is my result over 10 mg/L?
Levels that high usually point to an infection, injury or inflammatory condition rather than heart risk. Guidance is to look for the cause and repeat the test later.
Do I need to fast?
hs-CRP itself can be drawn fasting or not, but it is often bundled with tests that do need fasting.
Sources
We cite government agencies, professional societies and peer-reviewed research. See our editorial policy.
- C-reactive protein (CRP) testMedlinePlus (U.S. National Library of Medicine)
- Markers of Inflammation and Cardiovascular Disease: A Statement for Healthcare Professionals (2003)Centers for Disease Control and Prevention / American Heart Association
- 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular DiseaseAmerican College of Cardiology / American Heart Association