Use of procalcitonin in the diagnosis of tuberculosis in infants and preschool children

Eneritz Velasco-Arnaiz, Esther Pérez, Desirée Henares, Anna Fernández-López, Anna Valls, Pedro Brotons, Clàudia Fortuny, Antoni Noguera-Julian

Normal procalcitonin (PCT) levels have been reported in adult pulmonary tuberculosis (TB) but have not been previously investigated in children. We aimed to assess PCT levels at diagnosis of TB in young children in a low-burden setting. In a cross-sectional observational study in a referral pediatric center in Barcelona (Spain), we assessed the value of PCT and other inflammatory markers (leucocyte counts, C-reactive protein, and erythrocyte sedimentation rate) in the diagnosis of TB in pre-school children (< 6 years at diagnosis, n = 45), as compared with two control groups (pneumococcal pneumonia, n = 25; and healthy controls, n = 49). Normal PCT levels were observed at diagnosis of TB in most cases, while C-reactive protein values and leucocyte counts were slightly elevated when compared to healthy controls. All three inflammatory biomarkers were significantly higher in children with pneumococcal pneumonia. In our study, PCT was not a useful diagnostic test for TB in young children. In a low-burden TB setting, PCT may be of some value in distinguishing pulmonary TB from pneumococcal pneumonia. What is Known: • Diagnosis of pediatric tuberculosis on clinical evidence is difficult, particularly in infants and small children. • Studies in adults with tuberculosis have mostly reported normal procalcitonin levels at diagnosis. What is New: • In pre-scholars with tuberculosis, erythrocyte sedimentation rate and white blood cell counts were higher than in healthy controls, but procalcitonin was not. • Procalcitonin may be useful in the differential diagnosis of intrathoracic tuberculosis and pneumococcal pneumonia.