Reliability of real-time reverse-transcription PCR in clinical diagnostics: gold standard or substandard?

Molecular diagnostics is one of the major growth areas of modern medicine, with real-time PCR established as a qualitative and quantitative technology that is rapid, accurate and sensitive. The sequencing of the human genome, comprehensive genomic, mRNA and miRNA expression profiling of numerous cancer types, the ongoing identification of disease-associated polymorphisms and the expanding availability of genomic sequence information for human pathogens has opened the door to a wide range of translational applications for this technology. Consequently, novel real-time PCR assays have been developed for diagnosis and prognosis, treatment monitoring, transplant biology and pathogen detection, as well as more controversial uses such as lifestyle genotyping. However, this technology is still troubled by significant technical deficiencies. Hence its often-improper use as a clinical tool has important public health implications, most recently demonstrated through its association with the measles, mumps and rubella vaccine/autism controversy. This serves as a timely reminder of the indispensable requirement for careful experimental design, validation and analysis.