It is important for clinicians handling patient cases that warrant urine drug screenings to keep the following summary in mind to ensure the results reflect the diagnosis or information needed.
Urine Drug of Abuse Screens are performed in hospital labs by a series of immunoassays using antibodies that specifically react with classes of drugs. The drugs detected are Amphetamines, Barbiturates, Benzodiazepines, Cannabinoids, Cocaine metabolites, Methadone, Opiates, and Phencyclidine. The presence of other drugs is not detected. These are screening tests and are designed to be very sensitive, but like all screening procedures are not completely specific. Specificity is adequate for most medical purposes. However, if definitive results are required, Gas Chromatography - Mass Spectroscopy (GCMS) should be requested for absolute identification. This is especially important if the information is extremely sensitive to the patient, or if there is any forensic implication. GCMS confirmations are sent to a reference laboratory and require 24 to 48 hours for completion.