Differences between standard and high-sensitivity immunohistology in tissue sections--comparison of immunoperoxidase staining methods using computerized video image analysis techniques.

High-sensitivity immunoperoxidase labelling can be achieved using heavy metal enhancement of the di-amino (DAB) reaction product. For example nickel chloride combined with DAB improves the sensitivity of the method approximately 7-10 fold. This allows detection of approximately 100-200 molecules on cell surfaces. This has an obvious advantage over standard non-enhanced DAB methods which detect 1000-2000 molecules under similar conditions. This study compares standard and nickel enhanced DAB immunoperoxidase staining of cells in tissue sections using video-image analysis (VIA) measurement techniques. VIA is an objective method of evaluation of immunoperoxidase staining of separated cells and for immunostained cells in tissue sections. Nickel enhancement of the DAB reaction product reveals more positively stained cells, with higher contrast over background, giving superior qualities for VIA analysis providing continuous, reproducible, and objective data for statistical analysis.