The diagnostic value of urinary culture filtrate protein-10 antigen in childhood tuberculosis

Introduction and Aim: Childhood tuberculosis (TB) remains a major problem worldwide. However, diagnosis of tuberculosis in children is often complicated by the difficulty in obtaining a proper sputum specimens and low sensitivity of the gold standard diagnostic test to confirm the presence of Mycobacterium tuberculosis (M.tb) in this age group. Recently, M.tb antigen detection in urinary specimens has become a popular method. It is non-invasive and handling of specimen is simple. It was reported that urinary CFP-10, a specific protein of M.tb, has emerged as a potential biomarker in the future. However, its diagnostic value as a new biomarker in childhood TB remains poorly understood. The aim of the study is to determine the diagnostic value of urinary CFP-10 in childhood TB. Methods: Seventy children with suspected pulmonary or extra pulmonary TB were enrolled. Tuberculosis was diagnosed by performing Tuberculin skin test, chest x-ray, microscopic examination, and microbiological culture obtained from sputum or gastric lavage specimen. The level of urinary CFP-10 antigen was analyzed by ELISA (Elabscience, China). Statistical analyses were performed using SPSS 21.0 and p-values of <0.05 were considered statistically significant. Results: The levels of urinary CFP-10 in subjects diagnosed with TB was higher than that of the non-TB subjects, 4.13(0.62) vs 0.43(0.14) pg/mL, p=0.005. The cut-off value for urinary CFP-10 level reached 0.39 pg/mL (sensitivity 65% and specificity 67%). This value became 0.54 pg/mL (sensitivity 61% and specificity 62%) in microbiologically confirmed cases. Conclusion: The urinary CFP-10 level has moderate diagnostic value for diagnosing childhood TB.