Gram Stain
Use
Determine the presence of microörganisms and to evaluate the type of specimen by type of cells seen (eg, PMN, epithelial)
Special Instructions
Ensure that the source of the specimen is indicated on the test request form. Label both the slide and slide holder. Gram Stains should be used in conjunction with anaerobic cultures for certain specimens and are recommended for demonstrating specific pathogens like Neisseria gonorrhoeae or Mobiluncus in genital specimens. It is important that a valid sputum specimen is obtained and additional specimens submitted if contamination is suspected.
Limitations
The Gram Stain has limitations, such as not typically leading to the staining of mycobacteria, which require an acid-fast stain, and its sensitivity varies with organism type and presence. Certain bacteria like Legionella pneumophila do not stain well or at all. The Gram Stain is less reliable for diagnosing cervical, rectal, pharyngeal, or asymptomatic urethral gonococcal infections. Misidentification of bacteria due to similar staining properties can also occur. Additionally, the Gram Stain is ineffective in cases where the bacterial load is low.
Methodology
Culture-based
Biomarkers
LOINC Codes
- 664-3
- 664-3
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
Not provided
Minimum Volume
Not provided
Container
Clean glass slides, swab in transport or clinical material in sterile container
Collection Instructions
Carefully select material from infected area with a sterile swab. Gently roll swab onto a clean glass slide to make a thin smear. Air dry the slide. Do not fix.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Inappropriate specimen transport device; improper labeling; specimen received after prolonged delay (usually more than 48 hours); stool or fecal source.
Other tests from different labs that may be relevant