Cartridge Based Nucleic Acid Amplification Test: Utility as Diagnostic Modality in Clinically Diagnosed Childhood Tuberculosis

Introduction: Tuberculosis (TB) remains one of the deadliest communicable diseases worldwide. The introduction of early and rapid diagnostic test such as Cartridge Based Nucleic Acid Amplification Test (CBNAAT) creates opportunities for improvement in early and fast detection of TB and drug-resistance. Aim: To determine the prevalence of Tubercular cases in clinically diagnosed TB patients and to determine the prevalence of Rifampicin resistance by CBNAAT. Materials and Methods: This prospective observational study involved a total of 107 children from January 2018 to June 2019, fulfilling the inclusion criteria who were clinically diagnosed and found positive in conventional tests for TB. CBNAAT was used to confirm Mycobacterium tuberculosis (MTB) for the diagnosis of childhood TB and compare with other conventional methods. Chi-square test for the proportion was applied and p-value <0.05 taken as significant. Results: Of the 107 patients studied, 44.9% were female and 55.1% were male. The age range was 3 months to 12 years. The cases were confirmed by CBNAAT in clinically suspected case of TB was found to be 17.8% (19 cases out of 107 patients). CBNAAT was able to detect MTB in 14% (15 cases out of 107 patients) of the gastric aspirate/sputum sample. Out of 107 patients, 69 children were clinically diagnosed as Neurotuberculosis and 13% (9 out of 69 cases) cases were confirmed by CBNAAT in Cerebrospinal Fluid (CSF). OF which 29 patients had CSF analysis suggestive of Tubercular Meningitis (TBM). Out of 29 patients, 10 (34.5%) cases were confirmed by CBNAAT. This test showed a significant association with positive Mantoux test (p-value 0.020) and CSF analysis (p-value 0.021) suggestive of TBM. Conclusion: CBNAAT should be used in preference to conventional methods as the initial diagnostic test for patients suspected of having TB. CBNAAT positivity shows significant association with positive Mantoux test and CSF analysis suggestive of TBM.