When Is Gram Staining Used?

A Gram stain is most often used to find out if you have a bacterial infection. If you do, the test will show if your infection is Gram-positive or Gram-negative.

What does a Gram stain test for?

A Gram stain is a laboratory procedure used to detect the presence of bacteria and sometimes fungi in a sample taken from the site of a suspected infection. It gives relatively quick results as to whether bacteria or fungi are present and, if so, the general type(s).

Why is the Gram stain so useful?

The Gram stain is the most important staining procedure in microbiology. It is used to differentiate between gram positive organisms and gram negative organisms. ... It is thought that this happens because the cell walls of gram positive organisms include a thick layer of protein-sugar complexes called peptidoglycans.