Definition

CRP is a blood protein produced by the liver in response to inflammation. The test measures its level in the blood.

Purpose

Evaluates signs of bacterial infection (fever, chills, rapid heartbeat, rapid breathing, nausea/vomiting). Checks for chronic inflammatory conditions. Monitors post-surgical infection. Tracks treatment effectiveness. Assesses sepsis risk.

Results

CRP levels are very low in healthy individuals. High values indicate inflammation, but do not show the cause or location.

Normal Values

0.8 to 1.0 mg/dL and below is considered healthy. (May vary by laboratory.)

The difference between CRP and hs-CRP: Standard CRP detects acute or chronic inflammatory conditions. hs-CRP (high-sensitivity CRP) measures very small increases in CRP and is used to estimate heart disease risk. The two serve different purposes.

Risks and Limitations

CRP shows the presence of inflammation, not its cause, source, or which disease is present. Non-inflammatory factors can also raise it: sleep deprivation, depression, hormone therapy, obesity, and female sex.

Related Tests

Erythrocyte Sedimentation Rate (ESR)

Measures the time it takes for red blood cells to settle to the bottom of a tube. The faster the red blood cells clump together and settle, the more inflammation there is in the

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ANA (Antinuclear Antibody)

The immune system produces proteins called antibodies to fight foreign substances such as viruses and bacteria. Antinuclear antibodies, however, mistakenly target healthy cells.

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RF (Rheumatoid Factor)

Detects a protein produced by the immune system that mistakenly attacks healthy antibodies (IgG) instead of germs. It is an autoimmune marker, not an indicator of infection.

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Other related tests not yet in the glossary: CCP Antibody, Complement, Procalcitonin.