Cerebrospinal fluid (CSF) and all specimens collected from sterile sites should have a microscopic examination performed along with culture. Bacteria found in CSF, blood, tissue, and specimens from other sterile sites are always significant.
CSF should be cytospun, if possible, to increase the chance of detecting a pathogen. The number of organisms seen and the amount and type of host cells (eg, mononuclear or polymorphonuclear [PMN] white blood cells) are important to report. The presence of PMNs indicates a bacterial infection. It is also important to determine and report whether the bacteria are found inside (intracellular - phagocytosis) or outside (extracellular - colonizing bacteria) the white blood cells.
