Procalcitonin, Crp, and Esr for the Diagnosis of Acute Pyelonephritis in Children

Summary

A Cochrane review [Abstract] 1 included 36 studies evaluating the results of an index test, procalcitonin (PCT), C-reactive protein (CRP), or erythrocyte sedimentation rate (ESR) against the results of an acute-phase 99Tc-dimercaptosuccinic acid (DMSA) scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of urinary tract infection (UTI). Twenty-five studies provided data for the primary analysis: 12 studies (n=1 000) included data on PCT, 16 studies (n=1 895) included data on CRP, and 8 studies (n=1 910) included data on ESR. Cut-off values used were: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/hour for ESR.

All 3 tests were found to be sensitive (summary sensitivity values ranging from 0.81 to 0.93) but not very specific (table T1). The ESR was not sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) was somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevented to make recommendations. The procalcitonin test seemed to be better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevented to reach definitive conclusions.