If someone was taking prednasone when they took the secretor test, could it make them test as a secretor when they're actually a non-secretor?

no.

prednasone would not alter or eradicate the antigen content of your saliva or add antigens

is that the same medication than prednison??)...so it's a corticosteroide....people under such circumstances will have changements in their tests, so I can't Vegatest em :-/.....:P.....will show up false results, coz of the antiinflamatory issue ::) :-/.....(whistle)