What is the role of gram stains in the emergency department (ED) evaluation of gonorrhea?

Updated: Sep 07, 2018
  • Author: Brian Wong, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Answer

Gram stain is a rapid and inexpensive test available in many emergency departments (EDs). The positive predictive value is high for urethral infection, but a negative Gram stain does not rule out infection in asymptomatic men. Collect specimens from the urethra, endocervix, pharynx, rectum, conjunctiva, urine, or blood.

A Gram stain of urethral or cervical discharge may show gram-negative intracellular diplococci (diagnostic in the male) and PMNs. This is very useful if the physician has easy access to a microscope, because the diagnosis may be made without waiting for culture results.

The sensitivity and specificity of the Gram stain are lower for endocervical and rectal specimens. Gram stains from these sites are not recommended for routine use in the ED. In addition, Gram staining is not useful for the diagnosis of pharyngeal infection, because the oropharynx may be colonized by other Neisseria species that can lead to false-positive results.


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