Gram Stain

This is a test to identify the cause of a bacterial infection so appropriate treatment can be given. A Gram stain is used to determine if bacteria are present in an area of the body that is normally sterile, such as spinal fluid. A sample of cells or fluid is taken from the infected area is smeared on a glass slide and allowed to dry. A series of stains and a decolorizer is applied. The stained slide is then examined under a microscope where bacteria appear either purple (gram positive) or pink (gram negative).

A Gram stain can determine the type of bacteria causing an infection such as pneumococcal pneumonia or a staphylococcal abscess and can help your caregiver identify appropriate antibiotics to treat the infection.


Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.