What should you know about an hs-CRP blood test?

High-sensitivity C-reactive protein is made by the liver when inflammation is present. The test uses a blood sample and can detect small changes, but the result is non-specific. A recent infection, injury, ongoing inflammatory illness, or other temporary change may affect it. Conditions such as coeliac disease, Crohn's disease, kidney disease, and some infections can be considered alongside symptoms and other tests.

Follow the laboratory or clinician instructions about medicines, food, and the appointment. Tell the clinician about recent illness, injury, fever, or long-term conditions. The result should be read with your history, examination, and other investigations; do not diagnose yourself from a flagged value. Ask what follow-up is needed and whether repeating the test when you are well would clarify the picture.

The blood test itself is routine, but seek prompt medical care for severe breathlessness, chest pain, confusion, fainting, a stiff neck, or rapidly worsening illness. Contact your clinician about an unexpected result, persistent fever, ongoing fatigue, or symptoms that are getting worse. Urgency depends on the symptoms and examination, not the hs-CRP result alone.

Why was hs-CRP requested in my situation? Could a recent illness have influenced it? Which other results should be considered with it? Do I need repeat testing or assessment for a specific cause?