Zinc oxide is the metal zinc that has been oxidized. The chemical formula is ZnO, 1 zinc atom and 1 oxygen atom held together by an ionic bond. Zinc oxide does occur in nature as the mineral zincite, but it is quite rare and commercially unavailable.
I have done a few stool samples in my time and have always just stored them in the fridge, until the next day to take them into the docs. Good luck hun I hope they get it sorted.
For best results, the stool should then be brought to the laboratory immediately. If the stool specimen is going to be examined for an infection, and it's impossible to get the sample to the laboratory right away, the stool should be refrigerated, then taken to the laboratory to be cultured as soon as possible after collection.