Molecular diagnostics in virology

Molecular biology has significantly improved diagnosis in the field of clinical virology. Virus discovery and rapid implementation of diagnostic tests for newly discovered viruses has strongly beneficiated from the development of molecular techniques. Viral load and antiviral resistance or subtyping assays are now part of the biological monitoring of patients chronically infected by human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and CMV. It will be important to add to this panel assays for other viruses of the herpesviridae family. Qualitative assays for the detection of blood-borne viruses have increased safety of blood donation and organ transplantation. Screening of other blood-borne viruses (parvovirus B19, HAV), multiplexing of detection and test automation to improve practicability and reduce costs will be the next steps. A major evolution in the near future will be the generalization of NAT for the diagnosis of viral etiology in patients, mostly with respiratory, CNS or gastro-intestinal diseases. Major technical improvements have been made to avoid obstacles that still limit this generalization, i.e. genetic variability of viruses, multiplex detection, contamination risk. Commercial offers already exist but menus must be extended to limit the validation and documentation work associated with home-brew assays. Real-time amplification has allowed the development of new NAT platforms but automation and integration of all steps of the reaction are still required to reduce hands-on-time, time-to-result and costs, and to increase throughput.