Introducing a molecular test into the clinical microbiology laboratory: development, evaluation, and validation.

Abstract

In the mid-1980s, the polymerase chain reaction methodology for the amplification of minute amounts of target DNA was successfully developed and then introduced into clinical use; such technology has led to a revolution in diagnostic testing. Despite enormous advances in the detection of infectious agents by amplification methods, there are also limitations that must be addressed. To highlight the pertinent steps and issues associated with the introduction of an amplification assay into a clinical microbiology laboratory as well as the subsequent ongoing activities following its introduction into routine laboratory use. Data were obtained from literature searches from 1990 through September 2002 using the subject headings "polymerase chain reaction," "molecular assays," and "amplification" as well as publications of the National Committee for Clinical Laboratory Standards. Using the findings obtained from these studies and publications, the process of introducing a molecular assay into the clinical microbiology laboratory was broken down into 4 major components: (1) initial phase of assay development, (2) polymerase chain reaction assay verification in which analytic sensitivity and specificity is determined, (3) assay validation to determine clinical sensitivity and specificity, and (4) interpretation of results and ongoing, required activities. The approach, as well as the advantages and limitations involved in each step of the process, was highlighted and discussed within the context of the published literature. The application of molecular testing methods in the clinical laboratory has dramatically improved our ability to diagnose infectious diseases. However, the clinical usefulness of molecular testing will only be maximized to its fullest benefit by appropriate and careful studies correlating clinical findings with assay results.