Direct microscopic examination (or Direct smear) typically refer to microscopic examination of a specimen before any culture or inoculation is performed.
Can direct smear help detect contamination of clinical samples during sample collection (e.g. contamination of blood culture by skin flora during venipuncture)?
"A situation in which three different morphotypes (cellular types) are seen on direct Gram stain, but more than three organisms are on the culture plate indicates possible contamination." (Bailey & Scott's Diagnostic Microbiology, 13th edition.)
Does this "contamination" refer to contamination in-lab contamination post direct smear, where the number of culture isolates > morphotypes?
Or, does it refer to contamination prior to direct smear, where the contaminant biological count was insignificant to be noticed by microscope but they grew after culturing?