Alterations of peripheral leukocyte count, erythrocyte sedimentation rate, and C-reactive protein in febrile urinary tract infection.

INTRODUCTION: The aim of this study was to assess the usefulness of peripheral leukocyte count, differential leukocyte count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in febrile urinary tract infection (UTI) for defining the UTI level. MATERIALS AND METHODS: A total of 61 children aged between 1 and 10 years with documented febrile UTI (axillary temperature > or = 38 degrees C) were studied. They had a urine culture positive for infection. Laboratory investigations including peripheral total and differential leukocyte counts, ESR, and CRP were assessed in relation to the inflammatory responses. Leukocyte count results were available in all of the patients, ESR in 41, and CRP in 36. RESULTS: Leukocyte count was normal in 6 patients (9.8%). Lymphocytic leukocytosis was seen in 1 patients (1.6%), neutrophilic leukocytosis in 25 (41.0%), and relative neutrophilia in 29 (47.5%). Thirty patients (73.2%) had a high ESR and 23 (63.9%) had a positive CRP. In children with a high ESR, 12 (29.3%) had neutrophilic leukocytosis and 14 (34.1%) had relative neutrophilia. Relative neutrophilia and neutrophilic leukocytosis with positive CRP both were found in 11 patients (30.6%). Negative CRP with absence of neutrophilic leukocytosis was found in a significantly higher proportion of patients. There were no direct correlations between the severity of systemic inflammatory responses and urinary tract inflammatory response. CONCLUSIONS: Findings of this study showed that ESR and differential leukocyte count are two valuable tests in febrile UTI and may be useful for localization of UTI level, but the total leukocyte count and CRP level as in qualitative methods are not useful, and many patients with febrile UTI do not have leukocytosis.