Home Biomarkers CRP

CRP

Inflammation Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Inflammation

Overview

C‑reactive protein (CRP) is an acute‑phase protein produced by the liver in response to inflammation (mainly driven by IL‑6). The blood test measures circulating CRP concentration as a nonspecific marker of inflammation or tissue injury. Elevated CRP can indicate bacterial infection, sepsis, autoimmune disease flares (e.g., rheumatoid arthritis, lupus), inflammatory bowel disease, trauma, or certain cancers; a high‑sensitivity CRP (hs‑CRP) assay is used to assess cardiovascular risk. Symptoms that prompt testing include fever, unexplained pain, redness or swelling, or monitoring treatment response. Levels vary with age, obesity, smoking, pregnancy and some chronic conditions.

People also test for

Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Inflammation - Symptoms: fever, malaise, localized pain, swelling, or suspected infection/inflammation - Used to diagnose/monitor: infections, autoimmune flares, post‑operative inflammation, response to therapy - Reasons for abnormal levels: acute infection, chronic inflammatory disease, tissue injury, malignancy - Biological meaning: elevated CRP = active acute‑phase inflammatory response - Behaviors causing rise: smoking, obesity, poor diet, inactivity, heavy alcohol use - Family history: early cardiovascular disease may prompt hs‑CRP testing

Run our symptom checker to see if this test is right for you

Symptom Checker

Understanding Test Results

Standard CRP: <10 mg/L is generally considered normal/absent significant acute inflammation.
10–50 mg/L suggests mild‑to‑moderate inflammation (viral infections, autoimmune activity, chronic inflammatory states).
50–100 mg/L indicates substantial acute inflammation often due to bacterial infection, major trauma or surgery.
>100 mg/L strongly suggests severe bacterial infection or sepsis and requires urgent evaluation.
hs‑CRP (for cardiovascular risk): <1 mg/L low risk, 1–3 mg/L moderate risk, >3 mg/L high risk.
Readings >10 mg/L usually reflect acute illness and should be rechecked after recovery before using hs‑CRP for CV risk assessment.
Low CRP is not typically clinically concerning.

Normal Range

<10 mg/L OR <3 mg/L

FAQs

Q: What does CRP mean if it's high?

A: CRP (C‑reactive protein) is a blood marker that rises with inflammation. A high CRP level suggests acute infection, tissue injury, autoimmune or chronic inflammatory conditions and can indicate higher cardiovascular risk. It’s nonspecific, so an elevated result requires clinical correlation and further tests to identify the underlying cause and guide appropriate treatment.

Q: What infection causes CRP?

A: C-reactive protein (CRP) is not caused by a single infection; it’s a liver-produced marker that rises whenever inflammation occurs. CRP increases with many infections especially bacterial ones such as pneumonia, sepsis, urinary tract infections and cellulitis but also with viral, fungal, or parasitic infections. Noninfectious inflammation (autoimmune disease, trauma, surgery) can also elevate CRP; higher levels often indicate more severe inflammation.

Q: What is the CRP normal range?

A: CRP (C‑reactive protein) is normally under about 10 mg/L; values below 10 mg/L generally indicate no significant acute inflammation. For high‑sensitivity CRP (hs‑CRP) used in cardiovascular risk, <1 mg/L is low risk, 1–3 mg/L average risk, and >3 mg/L higher risk. Values above 10 mg/L usually reflect acute infection or significant inflammation and warrant further evaluation.

Q: How to treat high CRP levels?

A: Treating high CRP focuses on finding and managing the underlying cause: diagnose and treat infections or inflammatory diseases, and control chronic conditions (diabetes, hypertension, high cholesterol). Lifestyle changes—smoking cessation, regular aerobic exercise, weight loss, a Mediterranean anti‑inflammatory diet, and limiting alcohol—reduce CRP. Doctors may prescribe medications (e.g., statins or anti‑inflammatory therapy) and repeat CRP testing to monitor response.

Q: Can stress cause high CRP?

A: Yes. Psychological stress—especially chronic stress—can raise systemic inflammation and CRP. Stress activates the hypothalamic–pituitary–adrenal axis and sympathetic nervous system, boosting pro‑inflammatory cytokines (e.g., IL‑6) that stimulate CRP production. Acute stress may cause transient rises; chronic stress, poor sleep, and unhealthy behaviors can sustain higher CRP, which is linked to increased cardiovascular risk.

Q: Is CRP 200 high?

A: Yes a CRP of 200 mg/L is very high and indicates significant acute inflammation. Levels this elevated are commonly seen with serious bacterial infections, sepsis, major trauma, or severe inflammatory conditions. It requires urgent medical assessment, additional investigations to find the cause, and prompt treatment tailored by a healthcare professional.