Rapid Gram Stain

Rapid Gram Stain
Rapid Gram Stain


Rapid Gram Stain

  • Product code: ACMBS-10
  • Specifications: 4x20mL, 4x100mL, 4x250mL (Box)
  • Intended use: Intended for staining bacteria or fungal smear
  • Store temperature: 5℃~30℃
  • Expiry date: 24 Months

More Details

PrincipleMain componentsSample requirementTest procedureResult interpretationMethod limitationPrecautions


The Gram staining method was founded by the Danish physician Gram in 1884. At that time, it was discovered that Gram-positive bacteria had thicker cell walls, more layers of peptidoglycan network and dense cross-linking, and they were stained by Gram Later, the complex of crystal violet and iodine can be firmly retained in the wall, and it is not easy to be removed by the decolorizing solution and still presents purple. On this basis, a Gram staining solution is formed.

Main components

Reagent compositionMain ingredient
1. Crystal violetCrystal violet, Ethanol
2. Iodine solutionIodine, Potassium iodide
3. DecolorizerAcetone, Ethanol
4. Safranin solutionFuchsin basic, Safranin, Ethanol

Sample requirement

  • Smear must pay attention to careful operation, smear thin and uniform. Preparation of the smear should be natural drying, heating fixed, the fixed temperature should not be too high, the heating limit is that when the back of the glass slide touches the back of the hand to feel warm rather than hot, otherwise it may change the morphology of bacteria and affect the observation.

Test procedure

  • 1. Add Crystal Violet for 10 seconds. Rinse with water gently, and then remove the excess water.
  • 2. Apply Iodine solution for 10 seconds. Rinse with water gently, and then remove the excess water.
  • 3. Add Decolorizer for 10~20 seconds. Rinse with water gently, and then remove the excess water.
  • 4. Counterstain with Safranin solution for 10 seconds. Rinse with water gently.
  • 5. Wait for smear to dry, and then examine the smear under a microscope.

Result interpretation

  • Gram-positive organisms appear purple.
  • Gram-negative organisms appear red.

Method limitation

  • False negative may occur when using the old specimen smear.


  • 1. The length of stain will depend on the specimen type and smear thickness, etc. For female leucorrhea smear, staining time should be slightly longer (more than 10 seconds) for better results.
  • 2. After the Decolorizer runs out, you can use acetone as a substitute decolorization solution, decolorization time can be slightly shorter.
  • 3. Blood culture specimens smear staining, if the negative bacteria staining is not prominent, prolonging Safranin solution staining time to 60 seconds, or use pure Safranin O solution (purchased separately) for counterstaining and the contrast between the negative bacteria and the background will be better.
  • 4. Reagent storage, try to avoid high and low temperature environment and direct sunlight.
  • 5. Winter temperature is too low, the staining time to be extended.
  • 6. The smear is too thick, the decolorization time is insufficient, and the crystal violet staining time is too long may cause false positive results. Excessive heat fixation of bacterial smears, too long bacterial culture time, and excessive decolorization may all lead to false negative results.
  • 7. This product should be used by professionals and interpretation of the results.
  • 8. Should carefully read the instruction manual before using. Can only be used before expiration date, and good personal hygiene protection.
  • 9. After use, disposal of waste should comply with the hospital or the environmental protection department requirements.
  • 10. The production date, production lot number and expiry date, see the packaging.

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