Abstract
Introduction: Gene-Xpert, CBNAAT is now approved test for early detection of tuberculosis. The interpretation of the result is done on the basis of cycle threshold in PCR study as High,Medium,Low and Very low. As Mycobacterium tuberculosis is a very slow growing bacteria,the culture takes time to give results.
Aims and objectives: This study is to correlate between the Ct value and growth in culture.
Methods: It was a prospective study which was conducted from July 2014 to June 2015.Bronchial washings,sputum,pleural samples(pleural fluid,pleural biopsies),tissue biopsy and other samples from patients of suspected tuberculosis were sent for direct smear/culture for AFB as well as Gene-Xpert.
Results: A total of 415 samples were analysed among which 163 was bronchial washings,71 were Sputum,Pleural samples was 98 and others (biopsies / FNAC and body fluids) were 83.Gene-Xpert was detected positive in 67 samples (bronchial washings -30,Sputum-15,Pleural samples-4,Others-18). Of the 67 patients who had detected positive in Gene- Xpert on the basis of Ct value total number of High was 6, Medium was 17, Low was 19 and Very low was 7. Among Low and Very low the culture showed no growth even after 8 weeks. Total 6 samples were detected High in which 3 had shown no growth 1 has shown growth at 3 weeks and 2 growth at 4 weeks. 17 Samples were detected medium in Gene-Xpert among which no growth found in 4 samples and growth seen in rest 13 samples before 6 weeks.
Conclusion: For detection of Mycobacterium tuberculosis in early stage Gene -Xpert is an excellent tool and on the basis of Ct value (Very low,Low,Medium,High) growth in culture can be anticipated and treatment can be started based on clinical judgement without waiting culture report.
- Copyright ©the authors 2016
