RESUMO
PURPOSE: The aim of this study was to compare the clinical usefulness of serum procalcitonin (PCT) levels in Mycoplasma pneumoniae pneumonia (M. pneumonia) and viral pneumonia in children. METHODS: We retrospectively analyzed the medical records of 348 patients admitted between June 2015 and December of 2015. There were 162 patients with M. pneumonia without virus coinfection (group 1) and 186 patients with viral pneumonia (group 2). All subjects had radiographic evidence of pneumonia with available specimens for both M. pneumonia and viral testing, and levels of serum PCT, white blood cell counts (WBC), neutrophil portion, and C-reactive protein (CRP). Fifty-eight children who performed follow-up sampling at the time of no fever for more than 48 hours were subdivided into group 3 (M. pneumonia with follow-up sampling, n=41) and group 4 (viral pneumonia with follow-up sampling, n=17). RESULTS: No difference was noted in the levels of serum PCT (P=0.168), CRP (P=0.296), WBC (P=0.732), and neutrophil proportion (P=0.069) between groups 1 and 2, after adjusting for age. Serial changes in serum PCT levels between the first and second samples were significant in group 3 (P=0.046). Serial changes in serum CRP levels between the first and second samples were significant in group 4 (P=0.008). CONCLUSION: Serum PCT and CRP levels may change differently after infection according to the etiology of pneumonia.