Present position of microscopy and of culture in diagnostic mycobacteriology.

The relative merits of microscopy and culture are discussed; it is attempted to review the possible reasons why microscopy is considered as unreliable in TB diagnosis, including the probably false application of Bayes' theorem. In the author's opinion, microscopy still holds a firm position in the rapid and relatively reliable detection of pulmonary TB. As for culture, it is highly questionable if "better media" could accelerate the growth rate of tubercle bacilli. Therefore, it should be attempted to introduce novel techniques which will allow to decrease considerably the mycobacterial mass needed for detection. Laboratories equipped with such devices could offer their services even on an intercontinental basis, in order to have a favourable cost-benefit ratio.