... meds on the weekends and on school breaks... he had a three week vacation over Christmas and on his first day back he took on 10mg pill at 8:00am and another at 12:00pm. Later that day he had to go to his doctor for a checkup for his meds and the doctor did a urinalysis and said the test detected no trace at all of the Ritalin, and said she could not prescribe him anymore. How long exactly does it take for the drug to be detected in a urinalysis? His doctor is aware of the fact that I do not give him the meds on days he doesnt have school and that he had been off school for three weeks and had only had two pills that day.Are there any published studies/reports on how long it takes before Ritalin can be positively detected in a urinalysis??