Platform
Company
Inflammation & Acute Phase
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Currently under review
Pending specialist review and validation.
C-reactive protein is a substance made by your liver that rises when there is inflammation in your body. The CRP test measures how much of this protein is in your blood. It is a general marker that signals your immune system is active, but it does not identify the exact cause.
CRP can increase with infections, autoimmune flares, or tissue injury, and it usually falls as inflammation improves. A related test called high-sensitivity CRP is used for long-term heart disease risk assessment, while the standard CRP test is typically used to evaluate more pronounced or acute inflammation.
Clinicians order CRP when you have symptoms that suggest inflammation, such as fever, pain, swelling, or fatigue, or to help monitor conditions like rheumatoid arthritis, vasculitis, inflammatory bowel disease, or infections. It is also used to follow recovery after surgery or injury and to assess response to treatments like antibiotics or anti-inflammatory medicines.
CRP by itself does not make a diagnosis, but it adds useful context to your story, physical exam, and other tests. For cardiovascular risk in people without acute illness, a high-sensitivity version may be chosen instead. Your care team considers CRP trends alongside other markers to understand what is driving inflammation and how it is changing over time.
A higher than usual CRP suggests active inflammation somewhere in the body, but it cannot pinpoint the source. Your clinician will interpret the result in context, comparing it with your symptoms, exam, and other tests. Changes over time are often more informative than a single value. Falling CRP can indicate that inflammation is resolving, while persistent elevation may suggest a chronic condition or ongoing stimulus.
If results do not match how you feel, timing, lab variability, or liver function could be factors. You might be asked to repeat the test or pair it with other markers or imaging. Do not start or stop medications on your own based on CRP alone; discuss the result and next steps with your clinician.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Tissue injury, operations, or even dental work can raise CRP temporarily. Your clinician will consider recent events when interpreting the result.
Corticosteroids, nonsteroidal anti-inflammatory drugs, and statins may lower CRP. Hormone therapy or certain birth control pills may raise it. Immunosuppressants can blunt the response.
Obesity, smoking, periodontal disease, and sleep apnea are linked with higher baseline CRP. Significant liver disease can reduce CRP production and may yield deceptively low results.
CRP changes quickly during illness. A sample taken very early or during recovery may be lower than expected. Repeat testing can help clarify the trend.
Baseline CRP can be modestly higher in pregnancy and in older adults. Newborns have unique patterns, so interpretation should be tailored to the clinical context.
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