Principles of HIV resistance testing and overview of assay performance characteristics.

HIV drug resistance testing is becoming an integral part of antiretroviral drug development and of patient management. The parameters that characterize the performance of both phenotypic and genotypic assays and the validation of this performance are essential to their proper use for these applications. Several principles and biological factors impacting drug resistance testing are summarized. Considerations regarding quality control and validation of the performance of genotypic and phenotypic assays are also addressed.