Role of Cartridge based nucleic acid amplification test (CBNAAT) in new sputum negative pulmonary tuberculosis

ABSTRACT

Introduction: Diagnosis of pulmonary tuberculosis in sputum negative patients for acid fast bacilli ischallenging till today. It is a fact that 50-60% patients of pulmonary tuberculosis are sputum negativemicroscopically. Smear microscopy is the easiest, commonest and widely employed tool for confirmatorydiagnosis of pulmonary tuberculosis, but it has low sensitivity and specificity. Sputum culture forMycobacterium tuberculosis bacteria can increase the diagnostic yield by 20-40%, but it takes long duration of2-8 weeks when solid media are used or 10-14 days when radiometric system in liquid media are used. Delayeddiagnosis causes increased rate of disease transmission in the community. The role of newly introducedcartridge based nucleic acid amplification test (CBNAAT) in the revised national TB control program (RNTCP)is highly promising with a higher yield of bacteriological diagnosis in sputum negative pulmonary tuberculosispatients with detection of rifampicin resistance within 2 hours only. Aims and objectives: The current study isto find out efficacy of CBNAAT in diagnosis of new sputum negative pulmonary tuberculosis patients. Thedetection of rifampicin resistance is also done in those patients. Materials and Methods: Sputum samples of100 sputum negative pulmonary tuberculosis patients were sent to District CBNAAT center in sterilized falcontube container. The CBNAAT result were analyzed. Results: Mycobacterium tuberculosis was detected inthirty one patients (31%). Not a single case was detected as resistant to rifampicin. Conclusion: CBNAAT helpsin increased case detection rate in lesser time in new sputum negative pulmonary tuberculosis patients.Rifampicin resistance was not detected in any patient.