11-07-2019, 12:38 PM
Certain medications or vitamin supplements may interfere with the validity of urine tests. Drug tests may provide false negative results as much as 10 to 15 percent of the time and false positives 5 to 10 percent of time. Oxycodone and some sedative or hypnotic drugs may be regularly missed, while cold medications or antibiotics may cause a false-positive result.5Oral drug tests may be very accurate at detecting amphetamines, cocaine and marijuana and determining current levels of impairment, although drugs are also not detectable for as long in saliva as they are in urine.2