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Gram stain |
| Test | Gram stain |
| Indication | Gram stain is a differential stain used to demonstrate the staining properties of bacteria |
| Physiology | Gram positive bacteria retain crystal violet dye after decolorization and appear deep blue. Gram negative bacteria are not capable of retaining the crystal violet dye after decolorization and are counterstained red by safranin dye. |
| Normal Range | Gram Positive/Gram negative |
| Interpretation | Gram stains is also done to detectt the presence or absence of white blood cells and squamous epithelial cells. Gram stain is the most valuable diagnostic test in bacterial meningitis. |
| Sample | Bacterial culture |
| Test Method | Gram staining |
| Related Tests | Fungus smear, Acid fast stain |
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