Differential staining

In microscopy and histology, staining is a technique to increase contrast in biological samples. Stains and dyes may interact with specific tissues, cell populations, organelles or proteins within the sample, which allows them to be more easily discerned or quantified.

Differential staining is the process of differentiating between different kinds of cells. In microbiology, there are various clinically useful differential stains. The most widely used is the Gram stain. For the identification of unknown bacteria, differential staining can be combined with other techniques, such as differential and/or selective media or biochemical tests.