The classic conditions for which inflammatory markers are recommended as first line are polymyalgia rheumatica (PMR), giant cell arteritis,7,8 and myeloma.9 Systematic reviews have also assessed the utility of CRP in diagnosing appendicitis,10 neutropenic sepsis11,12 and serious infection in febrile children,13,14 joint infection,15,16 chorioamnionitis,17 and several cancers in adults.18–23 These studies are mostly based in secondary care, so may be less applicable to primary care’s low disease prevalence settings. Here, CRP is linked to infection.