CRP and infection: Inflammatory markers, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and plasma viscosity (PV) are commonly used in primary care for diagnosis and monitoring of inflammatory conditions, including infections, autoimmune conditions, and cancers.1 Rates of inflammatory marker testing are rising, with a consistent linear increase in testing rates for CRP over the past 15 years.2 There is significant variation between GP practices in inflammatory marker testing rates and frequency of abnormal results.3