ORIGINAL ARTICLE: PDF OnlyMarshall Linda A.; Cubie, Heather A.Reviews in Medical Microbiology: July 1997 - p 157-170 Buy Abstract New technologies allow clinical specimens to be studied in ever greater molecular detail. In situ gene amplification (IS-GA) is a recent and exciting development which combines the exquisite sensitivity of the polymerase chain reaction with the cellular localization of in situ hybridization. Both direct and indirect IS-GA have been described. These differ in the way in which the amplified products are detected, and there are advantages and disadvantages with each. Since its first description in 1990, IS-GA has undergone many improvements in both specificity and sensitivity. No generally applicable protocols are available and technical problems still remain, particularly with the shorter, cheaper direct method. The complexity of IS-GA, along with concerns about efficiency and the ease with which false positives can be generated, have limited its use. Many different variables must be taken into consideration to achieve success, including specimen type, sample fixation and pre-treatment, PCR conditions, post-PCR treatments and product detection. In addition, stringent use of controls is essential for specificity. IS-GA has been used to study many different viruses and holds great promise in furthering our understanding of viral pathogenesis, following the effects of specific therapies, in diagnostics and in identifying infectious agents in diseases of unknown aetiology. It is particularly relevant for viruses which persist or remain latent at low copy number in different types of cell including retroviruses, herpesviruses and papillomaviruses. © Williams & Wilkins 1997. All Rights Reserved.