Urine drug monitoring is an important tool for substance misuse or abuse and adherence to the prescribed regimen. The most commonly used test is UDM by IA due to its low cost and quick results. However, it comes with an array of false-positive and false-negative results. Clinicians should seek definitive results by confirmatory testing prior to making changes that alter patient care, and all results should include discussions with the patient.
Clinical pharmacy specialists are generally an excellent and often untapped resource to provide guidance for interpretation of both IA and chromatographic testing. Clinical pharmacy specialists have an excellent understanding of the physical and medicinal chemistry properties of laboratory testing, a vast understanding of drug metabolites and interactions that might increase or decrease drug concentrations might account for possible false positives and false negatives, and they can help decipher unexpected results.
Finally, it is important to consider that UDM is done for patients and not to patients, with the ultimate goal of improving the safety of the patient and the public. Unexpected results should be discussed with patients to identify the underlying reasons, which may then warrant further intervention, such as definitive testing and ultimate referral to a substance abuse treatment program. Simply sending a discharge or medication discontinuation letter to a patient can create a confrontational situation rather than an educational opportunity for both patient and provider.