You Ordered the Urine Drug Test: Now What?
Urine drug testing (UDT) can be used for a variety of purposes. Traditionally, UDT has been used in the realm of nonclinical or forensic models of collection, interpretation, and result use. In fact, with the availability of drug testing kits through the Internet and neighborhood pharmacies, there are many people who know just enough about drug testing to get themselves and others into trouble. This article will focus on the appropriate clinical use of UDT, particularly from a “patient-centered” perspective, as part of a comprehensive Risk Evaluation and Mitigation Strategy (REMS). But to be clear, UDT must not be considered as more than part of a comprehensive REMS program; it may not even be the most important part, but simply a valuable clinical tool.
Ordering the “right test” for the “wrong purpose” can result in completely erroneous information being presented and applied to the clinical care of the patient. As an example, using a sophisticated quantitative laboratory test to assess drug compliance can result in a false sense of security if the test demonstrates the presence of the prescribed drug or the potentially incorrect conclusion of drug diversion if the drug appears to be absent.1 The fact is, drug testing requires a more sophisticated and sometimes nuanced approach when applied outside the highly structured realm of forensic science. The included case examples will help to illustrate these points.
UDT either can be something we do “to our patients” or something we do “for our patients.”2 It is particularly important that those ordering the tests are clear on this point before they require their patients to participate in a drug monitoring program. If even one person on the treatment team believes that the primary goal of the test is to catch patients who are doing something wrong, it will be very difficult to convince the patient that these tests are being done for their benefit, which, after all, should be the purpose behind all patient care.
This may be doubly challenging when state guidelines appear to mandate drug testing for all patients on chronic opioid therapy.3,4 To this point, the authors would suggest the following: just because someone tells you to do something, even if for the wrong reason, doesn’t necessarily make the practice a bad thing to do. Ultimately, it all comes down to how you use the results.
So, beyond any regulatory mandate for the clinical use of UDT, why do we bother? UDT can’t tell us whether the patient is taking the medications “exactly as ordered.” It can’t tell us whether the patient is “abusing or is addicted” to the prescribed medications. It certainly can’t tell us whether the patient is diverting some or all of their medication outside of the realm of legitimate medical use. However, it can help open a dialogue between patient and caregiver, sometimes raising important discussion points that might not come up during the normal course of clinical care, around the topic of risk management. Remember, the question isn’t “Is there risk?” If the patient has a pulse, they have risk. The real question is “What is that risk – low, medium, or high?” And most importantly, “How can that risk be managed?” Equally important is the question of “By whom?”2 Not all practitioners have the experience, comfort level, or resources to manage medium- or high-risk patients. Risk management is as much about patient selection as it is about choice of drug.5
Case Example #1
A 47-year-old investment banker with a past history of problematic alcohol use returns for his first follow-up appointment for chronic low back pain, which is being treated conservatively with physical therapy alone. At this time, the physician notices that his routine UDT is unexpectedly positive by immunoassay for “opiates.” The laboratory has specifically identified morphine and codeine in the sample. To the best of your knowledge, the patient did not disclose the use of any opioid medications at his initial consultation. What would be the most reasonable next step?
Certainly, the unexpectedly positive UDT needs to be explained. This could represent the illicit use of non-prescription opioids but it might also be something as simple as the undisclosed use of food containing poppy seeds.1,6 In this case, however, the answer is even more straightforward. The patient was prescribed Tylenol by his family dentist for a recent dental extraction. The patient had mentioned that while he used no medications regularly, he did indicate that he had recently taken Tylenol for some dental pain.
Of course, plain Tylenol (acetaminophen) cannot account for the presence of codeine/morphine in his urine drug screen, but acetaminophen with codeine can.7,8 In this case, the patient did not appreciate the importance of the distinction between plain Tylenol and Tylenol with codeine, which is a schedule III controlled substance. Checking your consultation notes, the patient did mention the use of Tylenol for dental pain, but the fact that the Tylenol was obtained by prescription was not recorded. Of course, in the time-limited context of a clinical encounter, such details often go unexplored or unrecorded. In the interest of efficiency, we’re all trained to filter out apparently extraneous information while we focus on information that seems to “fit” our diagnosis.
- Codeine metabolizes to morphine, so a patient legitimately using codeine as prescribed may be expected to have codeine/morphine in their urine sample.7,8
- In the limited amount of time available to a busy clinician, getting details about medication history (either provided as samples or prescribed) by other clinicians (including nurse practitioners and dentists) may be critical to prevent an “unexpected” result from becoming an “inappropriate” result, which could adversely affect the doctor–patient relationship.
- Educate yourself and your patients about all types of medications, both over the counter and prescription, which may influence treatment: communication is the key to a sound therapeutic relationship.2
Case Example #2
A 25-year-old man presents with chronic right leg pain, which is secondary to an open reduction with internal fixation of a compound fracture of the leg, after a motorcycle accident that occurred 9 months ago. The patient, who has multiple tattoos and body piercings, was started on sustained-release (SR) oxycodone (OxyContin) 10 mg twice daily. On the follow-up visit 2 weeks later, the dose of SR oxycodone was increased to 20 mg twice daily. A routine UDT was performed at this visit. At the third visit, the clinician noted that the patient’s urine drug screen is unexpectedly negative by immunoassay testing for “oxycodone,” which was supported by combined gas chromatography/mass spectroscopy (GC/MS) testing.