What it means
A quick lab test done on a sample such as sputum, urine, wound fluid or spinal fluid. The sample is stained with a purple dye, washed with alcohol and stained again with a pink dye. gram-positivegram-POZ-ih-tivDescribes bacteria that stain purple with the Gram stain because of their thick cell wall.Full entry bacteria keep the purple color; gram-negativegram-NEG-uh-tivDescribes bacteria that stain pink or red with the Gram stain because of the way their cell wall is built.Full entry bacteria lose it and look pink. The result, along with the bacteria's shape, helps the provider choose an antibiotic before the full culture is back. It is named after Hans Christian Gram, a Danish scientist.
At a glance
| Also written | Gram staining, Gram's stain |
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Related terms
culture and sensitivity
A lab test that grows the germs from a sample to identify them and see which antibiotics work against them.
gram-negative
Describes bacteria that stain pink or red with the Gram stain because of the way their cell wall is built.
gram-positive
Describes bacteria that stain purple with the Gram stain because of their thick cell wall.