C-Reactive Protein (CRP) Test: What It Is, Purpose & Results (2023)

FAQs

What is the purpose of CRP test? ›

Your health care provider might order a C-reactive protein test to: Check for infection. Help diagnose a chronic inflammatory disease, such as rheumatoid arthritis or lupus. Learn your risk of heart disease.

A high level of CRP in the blood can be a marker of inflammation. A wide variety of conditions can cause it, from an infection to cancer. High CRP levels can also indicate that there's inflammation in the arteries of the heart, which can mean a higher risk of heart attack.

The most common cause of high CRP levels is a severe infection. Other possible causes include a poorly controlled autoimmune disease and severe tissue damage. Read on to learn more about CRP levels, including how doctors check these levels, the normal ranges, and what can cause elevated levels in the body.

Interpretation of CRP levels:

Less than 0.3 mg/dL: Normal (level seen in most healthy adults). 0.3 to 1.0 mg/dL: Normal or minor elevation (can be seen in obesity, pregnancy, depression, diabetes, common cold, gingivitis, periodontitis, sedentary lifestyle, cigarette smoking, and genetic polymorphisms).

Angiotensin receptor blockers (ARBs) (valsartan, irbesartan, olmesartan, telmisartan) markedly reduce serum levels of CRP. The findings with other ARBs (losartan and candesartan) were inconsistent. Antidiabetic agents (rosiglitazone and pioglitazone) reduce CRP levels, while insulin is ineffective.

Or it may be a potentially life-threatening condition called sepsis or blood poisoning. Symptoms of sepsis may include fever and chills, headache, pain, nausea, vomiting, confusion, rash, and shortness of breath. The level of CRP in your blood goes up within a few hours of a serious infection.

Drawbacks of CRP tests

This is because CRP is not specific to RA. Elevated levels of CRP can indicate any infection or inflammatory condition. On the other hand, some people with RA may have normal CRP levels.

Third, CRP is only one of the inflammatory markers, and a recent study has reported that genetically predicted circulating concentrations of several inflammatory-related cytokines were associated with the risk of breast, endometrial, lung, ovarian, and prostate cancer [39].

For example, ultra-processed foods like fast food, frozen meals, and processed meats have been associated with higher blood levels of inflammatory markers like CRP ( 90 , 91 , 92 ).

The most common reasons for chronic inflammation include: Autoimmune disorders, such as lupus, where your body attacks healthy tissue. Exposure to toxins, like pollution or industrial chemicals. Untreated acute inflammation, such as from an infection or injury.

Can stress cause high CRP levels? ›

CRP is elevated in chronic stress and may be the link between stress and low-grade inflammation-related diseases. Scientists found that both psychological and social stress significantly impacts CRP [12].

Even if you have no symptoms of disease, elevated CRP signals increased risk for cardiovascular disease, cancer, diabetes, obesity, and more. Additionally, there's strong evidence that people with lower CRP levels have fewer inflammation-related diseases.

There's no doubt that the very best way to lower CRP is through exercise, weight loss, and dietary control; of course, those are all proven already to lower vascular risk.

CRP shows a rapid response to infection and inflammation, increasing within hours of stimulus and returning rapidly to normal following resolution. Typically CRP begins to rise within 4-6 hours of stimulus, peaks within 36–50 hours, and returns to normal 3–7 days following resolution.

Blood tests known as 'inflammatory markers' can detect inflammation in the body, caused by many diseases including infections, auto-immune conditions and cancers. The tests don't identify what's causing the inflammation: it might be as simple as a viral infection, or as serious as cancer.

This corresponds to a negative predictive value with respect to further treatment of 99% (95% confidence interval, 95.4% to 99.9%). The mean treatment duration was 3.7 (median, 4; range, 3 to 6) days in the CRP-guided group and 5.5 (median, 5; range, 5 to 7) days in the at least 5-day study group.

In addition to blood tests that measure inflammation, such as the CRP test, and antibodies, rheumatologists look at factors like physical symptoms and imaging, such as X-rays and MRIs.

Cherries. Cherries and other berries contain substances called antioxidants that help to calm inflammation. When people in one study ate 45 Bing cherries every day for about a month, their levels of CRP fell by 20%.

Discussion. In the present study, hypertension was associated with higher CRP levels in both men and women. Systolic BP and pulse pressure, but not diastolic BP, were associated with CRP.

It is important to note that several conditions can be associated with marked elevations of CRP levels, with infection being most common (particularly at extreme elevations). We could not distinguish between conditions based on the CRP level, but above 350 mg/L the cause was almost always infection.

What level of CRP indicates arthritis? ›

RA causes inflammation. In response, the body releases CRP into the bloodstream. Doctors measure CRP levels as part of the diagnosis and management of RA. While many factors influence a person's CRP levels, and there is no definitive normal range, CRP levels above 10 mg/l suggest substantial inflammation.

Low-grade inflammation can lead to fatigue. Higher CRP was linked with fatigue – both in healthy people and in disease-free survivors of breast cancer [27, 28, 29].

A few biologic compounds meet the criteria for an ideal tumor marker; C-reactive protein (CRP) is one [3]. It is a non-specific acute phase reactant which reflects tissue damage.

However, high levels of CRP were found to be strongly associated with advanced disease severity in numerous cancer types (elaborated below). Hence, CRP measurements have potential utility as a diagnostic tool in assessing disease status and progression, including in cancer.

There was no significant difference in change in circulating hs-CRP concentration between individuals consuming eggs relative to non-egg consuming controls (MD 0.24 mg L⁻¹, 95% CI: −0.43, 0.90, P = 0.48) with no evidence of heterogeneity between trials (I²: 53.8 %, Q statistics: 15.15, P = 0.03) (Figure 2).

A CRD with daily intake of eggs decreased plasma CRP and increased plasma adiponectin compared to a CRD without eggs.

When inflammation happens, chemicals from your body's white blood cells enter your blood or tissues to protect your body from invaders. This raises the blood flow to the area of injury or infection. It can cause redness and warmth. Some of the chemicals cause fluid to leak into your tissues, resulting in swelling.

Can high CRP cause pain? ›

Higher levels of CRP were associated with higher pain sensitivity ratings at pain threshold (p = 0.02) and tolerance (p = 0.03) after adjusting for age, body mass index, time to reach pain threshold or tolerance, and clinical pain status.

CRP is also useful as a laboratory marker to predict prognosis and relapse in patients with Crohn's disease and acute pancreatitis. Elevated CRP levels have been associated with an increased risk of colorectal cancer and are a marker of poor prognosis, indicating more advanced disease and, possibly, reduced survival.

CRP is elevated in chronic stress and may be the link between stress and low-grade inflammation-related diseases. Scientists found that both psychological and social stress significantly impacts CRP [12].

Whether a CRP level is dangerous will depend on the type of c-reactive protein test used, your individual medical history, and the suspected cause of inflammation. Your healthcare provider can best explain the test results to you. In general, anything above 1 mg/dL is elevated and may require intervention.