In a 2015 Cochrane review assessing procalcitonin for diagnosing acute pyelonephritis in pediatric patients,39 there were limited studies at the time of the review and marked heterogeneity of the included studies to recommend it for daily practice, although procalcitonin performed significantly better for ruling-in pyelonephritis compared to erythrocyte sedimentation rate or C-reactive protein. This evidence concerns the gene CRP and pyelonephritis.