Most raised hs-CRP results have an explanation that has nothing to do with your arteries. C-reactive protein goes up with almost any inflammation in the body, and also with excess body fat and some hormone treatments.
So a high number is a prompt to look for the cause and repeat the test when you are well. It is not a diagnosis of heart disease. Only a result that stays raised with no other explanation says much about heart risk.
Key takeaways
- hs-CRP is not specific to the heart, and mildly raised levels are very common.
- Recent illness, extra weight, inflammatory conditions and estrogen tablets are frequent reasons for a high reading.
- One result means little until it has been repeated at a time when you feel well.
- Tell your clinician about recent infections and all your medications before the result is interpreted.
How common a raised result is
A mildly raised CRP is ordinary. CRP levels between 3 and 10 mg/L are found in about one third of the American population.1 The same review found that even minor irritants and inflammatory triggers produce a small rise.
That is why the test needs context. For the ranges and how they relate to heart risk, see our hs-CRP test guide. This article is about the reasons behind a high number.
Short-term causes: illness and injury
CRP is part of your body's first response to trouble. The liver releases more of it soon after an infection or injury, and the level falls again as you recover. Common triggers include:
- a cold, flu, chest infection or urinary infection;
- a dental infection or recent dental work;
- a cut, sprain, burn or other injury;
- recent surgery.
A result far above the usual range points to something acute like this. It says very little about your long-term heart risk and should be repeated after you have recovered.
Body fat
Excess weight is one of the most common reasons for a persistently raised hs-CRP. Fat tissue releases chemical messengers that tell the liver to make more CRP.
In a national survey of 16,616 US adults, the odds of a raised CRP were about twice as high in obese men and about six times as high in obese women as in people of normal weight.2 A larger waist relative to the hips was linked to higher CRP regardless of overall weight.2
This cause overlaps with heart risk instead of competing with it. Fat around the middle is tied to insulin resistance, which raises cardiovascular risk through several routes.
Autoimmune and inflammatory conditions
Long-term inflammatory conditions keep CRP raised, sometimes well above the range used for heart risk. Examples are rheumatoid arthritis, lupus, psoriasis, inflammatory bowel disease and gout. A flare pushes the number higher still.
If you have one of these conditions, hs-CRP is a poor guide to what is happening in your arteries, because the signal from the condition drowns out everything else. These conditions are linked to heart risk in their own right, which we cover in autoimmune disease and heart risk.
Hormones
Estrogen taken by mouth raises CRP without any inflammation being present. The tablet passes through the liver first, and the liver responds by making more CRP.
In a small randomized crossover study of postmenopausal women, eight weeks of oral estrogen more than doubled CRP, while estrogen given through the skin had no effect.3 If you take hormone therapy as a tablet, tell your clinician before your hs-CRP is interpreted. Do not stop or change a prescribed medication to alter a test result.
A quick guide to the causes
| Cause | Typical pattern | Sensible next step |
|---|---|---|
| Infection or injury | Sudden rise, often large, that settles | Repeat once you have recovered |
| Excess body fat | Mild, steady elevation | Check weight, waist and metabolic labs |
| Inflammatory condition | Raised long term, higher in flares | Interpret with the clinician who manages it |
| Oral estrogen | Steady elevation while taking it | Mention it before the result is read |
| Smoking | Mild, steady elevation | Stopping helps on every count |
The list of associations is long. Researchers have linked minor CRP elevation to dietary patterns, to demographic and socioeconomic factors, and to many medical conditions that are not obviously inflammatory.1 Often no single cause is found.
When to repeat the test, and what a lasting result means
Repeat it when you are well. If you had any illness, injury or dental work around the time of the blood draw, wait until you have fully recovered. Your clinician can tell you how long to leave it.
What you are looking for is a pattern. A number that drops back to the low range was a passing event. A number that is still raised on a second test, taken when you feel fine, is more likely to be your true baseline.
If hs-CRP stays raised and nothing else explains it, it is read as a sign of low-grade inflammation that takes part in artery disease. Our article on inflammation and heart disease explains the link.
Even then it is one input, not a verdict. The US Preventive Services Task Force found the evidence insufficient to judge the benefits and harms of adding hs-CRP to standard risk assessment in adults without symptoms.4 It is most useful when a treatment decision is uncertain and the result could tip it.5
hs-CRP in a Cardio Res-Q assessment
hs-CRP is part of the lab panel in both Cardio Res-Q assessments: the Comprehensive Assessment ($775) and the Enhanced Assessment ($999). It is read beside ApoB, insulin, glucose and A1c, and beside your history, so that a raised number can be traced to a likely cause instead of being taken at face value.
If you have been unwell shortly before your visit, tell the team. See what to expect at your assessment, or go to the Cardio Res-Q program page to book.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Can being overweight alone explain a high hs-CRP?
Yes, it often does. Fat tissue drives CRP production, and the effect is stronger with fat carried around the waist. That does not make the result harmless, since the same excess weight raises heart risk in other ways.
I take estrogen tablets. Is my hs-CRP meaningless?
It is harder to interpret, not meaningless. Oral estrogen raises CRP through the liver, so your number may overstate inflammation. Tell your clinician, and do not change your prescription because of the test.
My hs-CRP came back very high. Should I worry about my heart?
A very high reading usually reflects an infection, injury or inflammatory flare, not artery disease. Mention any recent illness, and expect to repeat the test once you are well. If you feel unwell now, see a clinician about that.
Should I take an anti-inflammatory before the test to get a better number?
No. The aim is an honest baseline, not a low score. Take your usual medications as prescribed and tell the clinic what you take.
Related reading
This article is for general education and is not medical advice. Decisions about testing and medication should be made with your clinician. If you have chest pain or other symptoms of a heart attack, call 911.
