AbstractThe purpose of this study was to compare the performance of the alkaline phosphatase-streptavidin based detection systems from 3 commercially available kits for in situ hybridization. Of the 65 cases analyzed, 62 were known to contain human papillomavirus (HPV), 1 contained herpes simplex virus, and the other 2 cytomegalovirus by prior molecular analyses. The detection rates for the viral DNA using biotin-labeled probes were equivalent with the 3 detection systems, being 56/65 (86%) for the product from BioGenex, 53/65 (82%) from Digene, and 21/24 (87%) for Enzo Diagnostics. The BioGenex system yielded the overall strongest hybridization signal, defined by the intensity of the colorimetric reaction and number of positive cells. The Enzo system gave the lowest background signal. The Digene system was the easiest to use as it is a 1-step detection system as compared to a 3-step system for the other companies. We conclude that each of the kits is good for the detection of a target-probe complex for in situ hybridization and each offers advantages and disadvantages when compared to the other. (The J Histotechnol19:139, 1996)