Clinical application of rapidly emerging molecular technologies to elucidate, diagnose, and monitor human diseases is frequently referred to as molecular diagnosis. A broad definition of molecular diagnostics includes nucleic acid diagnostics, immunodiagnostics, and proteodiagnostics using proteomic technologies. Nucleic acid technologies use both DNA and RNA. The most important landmark in molecular diagnostics was the discovery of polymerase chain reaction in 1983. Although several other technologies for amplification and detection of nucleic acids have been developed since then, polymerase chain reaction, with its modifications, remains the mainstay of current molecular diagnosis of infectious diseases (Jain 2010).