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DIAGNOSTIC
METHODS: Concentrations
How
should the concentration wet preparation be examined?
The
most commonly used stool concentration method is the formalin-ethyl
acetate sedimentation. Zinc sulfate flotation will not detect
operculated or heavy eggs; both the surface film and sediment
will need to be examined before reporting a negative result.
Smears prepared from concentrated stool are normally examined
using the low power objective (10X) and the high dry power
objective (40X); use of the oil immersion objective (100X)
is not recommended (organism morphology not that clear). The
addition of too much iodine may obscure helminth eggs (will
mimic debris). |
