AbstractApplication of a manual capillary action workstation to colorimetric in situ hybridization is described. This system, commercially available as the MicroProbe system, is designed to take advantage of capillary action for the application of reagents, with subsequent reduction in technologist effort, conservation of reagents and reproducibility of results within an assay. The system can accommodate 20 slides, and results are comparable to those obtained with automated technology. Although the robotic system provides even greater freedom for the technologist and the ability to perform 60 slides per assay, the MicroProbe system provides a relatively inexpensive alternative for the introduction of new technology. (The J Histotechnol16:33, 1993)