Should I be able to pass?

[Burnt Toast]

take some aspirin and B vitamins a couple hours before my test. I've heard aspirin can cause false negatives.

It used to, but not anymore. Back in the day, aspirin interfered with only one type of test - the first generation EMIT screen. Since then, the EMIT II was introduced to counter the interference caused by aspirin. The first generation EMIT is seldom used anymore (if, at all).