How to use C-reactive protein.

A 3-month-old baby is brought to the paediatric emergency department by their parents because of a fever. You decide to check their inflammatory markers. Their C-reactive protein (CRP) level comes back as 20 mg/L. Does this affect whether or not you start antibiotic therapy? Does it influence your decision to admit or discharge the patient? CRP is a commonly used biochemical test and yet its use is constantly debated and challenged. We look at the current evidence and suggest the best way to use this test in clinical practice. © Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.