I'm getting a stomach empty test at 8am I took at 4:30am with very little water singular, Prevacid (lansoprazole) and ventolin will it be ok to get the test done.

Maybe... ...but it depends on the protocol being used, & context in which the test was ordered. By taking Prevacid, (lansoprazole) you reduced the volume of expected stomach contents, since the drug inhibits acid production. This may factor considerably in the rate of gastric emptying of the subsequently provided test meal. Please alert your Nuclear Medicine center on arrival.