KOH Preparation for Yeast represents the organisms isolated by culture. In the presence of a negative yeast culture, microscopic yeast may reflect organisms not viable enough to grow in culture. The presence of yeast on KOH prep should be correlated with the patient’s symptoms. However, moderate to many yeast suggests yeast overgrowth. A 1+ quantity of yeast is considered an acceptable amount of yeast in the stool. It may, however, reflect a condition of yeast overgrowth, especially when moderate or many yeast are reported on the microscopic (parasitology) exam, or may lead to symptoms in individuals showing deficient beneficial bacteria.