The undisputed success of detection assays based on the polymerase chain reaction (PCR) has been largely due to its rapidity in comparison to many conventional diagnostic methods. For instance, detection and identification of mycobacteria, chlamydiae, mycoplasmas, brucellae, and other slow-growing bacteria can be accelerated from several days to a single working day when clinical samples are directly examined. Other microbial agents that are difficult to propagate outside their natural host often remain undetected by techniques relying on cultural enrichment, thus rendering PCR the only viable alternative to demonstrate their presence. Additionally, there is the enormous potential of DNA amplification assays with regard to sensitivity and specificity.