A very few cases are detected Rifampicin (RIF) resistant(R) by GeneXpert MTB/RIF method but RIF sensitive(S) by AST result in MGIT960 (liquid culture) method. Both the results are getting from the same specimen of the respective patient. After getting GeneXpert result the patient is started MDR-TB treatment according to treatment category. But some clinician raise the question about the laboratory result in these short of cases. They asking why a few cases are happening like this discordant type of result? Which result should be considered finally?