Culture techniques are still seen as the gold standard for active TB as they are extremely sensitive, so long as live mycobacteria can be obtained in the sample. It is therefore the "gold standard" test which is used for comparison with other methods when calculating sensitivity in active disease. M. tuberculosis can be cultured from a variety of specimens including sputum, Central Spinal Fluid (CSF), pleural effusion, bronchoalveolar lavage (BAL), gastric aspirate etc and can thus be used to detect pulmonary as well as
non-pulmonary disease. By assessing the effect of antibiotics on the cultured bacilli, this technique can also identify the antibiotic susceptibility of the particular strain of TB infecting the patient. It is therefore the main method for identifying if a person has multi-drug resistant (MDR) TB. However, it is not always possible to obtain mycobacteria in the sample, especially in non-pulmonary TB so culture is not a sensitive test. If performed correctly it should have very high specificity and can distinguish M. tuberculosis from other mycobacteria. A drawback of this test is the time to result which can be anything from 2 to 6 weeks.