Gram – Cerebrospinal fluid (CSF): gram positive coccobacilli and lymphocytes – Shipped August 2014
A simulated CSF smear collected from an 84 year old female patient residing in a nursing home was sent to category A, B, C, and C1 laboratories for Gram staining.
Participants were expected to report the presence of lymphocytes or white blood cells (WBC), and gram positive bacilli.
MAIN EDUCATIONAL POINTS from GS142-1
- Laboratories unable to distinguish between mononuclear (e.g. Lymphocytes) and polymorphonuclear (e.g. neutrophils) cells on the Gram stain of sterile body site specimens should only report as white blood cells (WBCs) without type differentiation.
- Listeria monocytogenes maybe a difficult pathogen to identify on CSF smears but its correct identification as a gram positive bacilli/coccobacilli is important to guide clinicians to appropriate therapy.