Chapter 5 Clinical Applications of Quantitative Real-Time PCR in Virology

Engstrom-Melnyk, Julia; Rodriguez, Pedro L.; Peraud, Olivier; Hein, Raymond C.

Abstract Since the invention of the polymerase chain reaction (PCR) and discovery of Taq polymerase, PCR has become a staple in both research and clinical molecular laboratories. As clinical and diagnostic needs have evolved over the last few decades, demanding greater levels of sensitivity and accuracy, so too has PCR performance. Through optimisation, the present-day uses of real-time PCR and quantitative real-time PCR are enumerable. The technique, combined with adoption of automated processes and reduced sample volume requirements, makes it an ideal method in a broad range of clinical applications, especially in virology. Complementing serologic testing by detecting infections within the pre-seroconversion window period and infections with immunovariant viruses, real-time PCR provides a highly valuable tool for screening, diagnosing, or monitoring diseases, as well as evaluating medical and therapeutic decision points that allows for more timely predictions of therapeutic failures than traditional methods and, lastly, assessing cure rates following targeted therapies. All of these serve vital roles in the continuum of care to enhance patient management. Beyond this, quantitative real-time PCR facilitates advancements in the quality of diagnostics by driving consensus management guidelines following standardisation to improve patient outcomes, pushing for disease eradication with assays offering progressively lower limits of detection, and rapidly meeting medical needs in cases of emerging epidemic crises involving new pathogens that may result in significant health threats.