Usefulness of procalcitonin and C-reactive protein rapid tests for the management of children with urinary tract infection

Background. Urinary tract infection (UTI) is a common problem in children. Because clinical findings and commonly used blood indices are nonspecific, the distinction between lower and upper urinary tract infection cannot be m ade easily in this population. However, this distinction is important becau se renal infection can induce parenchymal scarring. The objective of this s tudy was to determine the accuracy of procalcitonin (PCT) compared with C-r eactive protein (CRP) rapid tests to predict renal involvement in children with febrile UTI. Methods. PCT and CRP were measured in the blood of children admitted to the emergency room with fever, signs and symptoms of urinary tract infection a nd/or a positive urine dipstick analysis. Renal parenchymal involvement was assessed by a (99)mTc-labeled dimercaptosuccinic acid renal scan in the ac ute phase of infection in all children. Sensitivity, specificity and likeli hood ratios were determined for both tests. Results. Fifty-four children with a proven urinary tract infection were enr olled: 63% had renal involvement; and 37% had infection restricted to the l ower urinary tract. No difference was found for age, sex and total white bl ood cell count between the groups. The calculated likelihood ratios of proc alcitonin and C-reactive protein rapid tests were between 3.8 and 7 and 1.5 and 2.8, respectively. A positive PCT value predicted renal involvement in 87 to 92% of children with febrile UTI, compared with 44 to 83% using CRP values. Conclusions. A rapid determination of procalcitonin concentration could be useful for the management of children with febrile UTI in the emergency roo m.