PCR (polymerase chain reaction) is a technique in molecular genetics that permits the analysis of any short sequence of DNA (or RNA) even in samples containing only minute quantities of DNA or RNA. RT-PCR is a PCR test that is designed to detect and measure RNA. Although initial PCR tests amplified DNA, many viruses and other biological components (for example, mitochondria) utilize RNA as their genetic material. For the detection of Mycobacterium tuberculosis complex (MTB), PCR is known to be sensitive, specific, and rapid compared to the conventional methods of acid-fast-bacilli (AFB) smear and culture.