text: whats the best way to pass a drug test?   according to jeff nightbyrd, there is testing industry data that taking 4 aspirins a few hours prior to the test might help you. ". . . aspirin interferes with the syvia [sic] emit assay. it seems that aspirin absorbs at the same wavelength that nad does which is how it interferes with the assay" (clin chem 34 (90) 602-606). two reliable sources have tested aspirin and found it to interfere with the emit. in the future they will try to find a way to circumvent this test flaw. until then, i certainly recommend taking advantage of the situation and using aspirin