You can use predictive tests, or more expensive lab test. A predictive test like Ehrlich's would test for LSD, and Marquis would suffice to check for amphetamines like DOx and even 5-MeO-AMT in such cases.
Probably drip a .5-1 ml of water on a white plastic or plate. Set your single blotter carefully in the water. Since the DOx and 5-MeO-AMT is a higher dosage its probably more likely to test 'brighter' I would test for those first, but we don't know the dosage of your blotter so Ehrlich's is best on a tight budget if buying premades.
Ehrlich's is made by 1% para-dimethylaminobenzaldehyde in 10% HCl(aq). Since its liquid we can assume volume, plus 10% HCl is only 0.048 g/ml heavier; so 100ml of 10%HCl we add .8g p-DMAB.
Add this to a blotter suspended in .5-1ml of water.