Urine drug testing for patients with substance use disorders (SUDs) can be a fraught topic if those patients are involved in the legal system. Tests that would otherwise be routine can have disastrous consequences. Here, we’ll review testing basics, describe how tests are used in legal settings, and advise you on how to order, interpret, and document results.

The basics of urine drug testing

There are two types of urine drug tests: a urine drug screen (UDS), which utilizes immunoassay technology, and a confirmatory test, which involves the use of gas chromatography–mass spectrometry (GC-MS).

Clinics throughout the world utilize the UDS; patients urinate into a cup and results are ready in a few minutes. These screens are quick and cheap but can be prone to false results. Amphetamine and opioid screens are notorious for false positive results due to antibody cross-reactivity, with one study finding a false positive rate of ~14% for amphetamines and ~34% for opioids (Johnson-Davis K et al, J Anal Toxicol 2016;40(2):97–107). For more information, see “Urine Drug Screens: What You Need to Know” in CATR May/June 2022.

Confirmatory testing is slower and more expensive but has a sensitivity and specificity approaching 100%, so it is usually reserved for UDS results that are being questioned. But even confirmatory tests cannot always be relied upon. For example, in 2021, the Department of Justice’s investigation into the laboratory testing company Averhealth revealed that up to 30% of drug test results that they provided to Michigan’s child welfare agency were false due to poor quality control and machine calibration issues (Hines A. Drug-Testing Company Used in Child Custody Cases Investigated for Fraud. Vice. January 27, 2023).

How drug testing is used in the legal system

Drug testing is routinely performed throughout the legal system with different considerations and potential consequences at each stage:

• Arrest. A positive drug test at arrest can result in higher bail or revocation of bail entirely.
• Pretrial. Drug testing may be a condition of pretrial release, with a positive result leading to reincarceration.
• Sentencing. A history of positive tests can lead to longer sentences.
• Incarceration. Inmates with a positive drug test may lose privileges or be subject to disciplinary action.
• Community monitoring. Drug testing is a common requirement during probation and parole. A positive test can result in stricter monitoring guidelines or even imprisonment.
• Child custody cases. Positive drug testing can lead to removal of the child from the home, limits on visitation, or loss of custody.

The UDS is the most common type of test used in the legal system, sometimes without confirmatory testing (Lang L. Investigation of New York State Department of Corrections and Community Supervision. State of New York Offices of the Inspector General. January 2022). Given the potential for false positives, there is widespread concern that people are being wrongfully arrested, convicted, or otherwise penalized (www.tinyurl.com/ycxear5x)[PDF]. One 2022 report found that over an eight-month period, 1,600 inmates were unjustly penalized with solitary confinement, denial of family visits, and delayed parole hearings based on false positive UDS results in the New York state prison system alone (Zraick K. N.Y. Prisons Punished 1,600 Based on Faulty Drug Tests, Report Finds. New York Times. January 4, 2022).

What can providers do?

Think before you order

Even if you work outside the courts, your records can be subpoenaed. Providers should order urine drug testing judiciously and only when clinically indicated. While a UDS can be an important tool, these screens can be prone to error, with potentially devastating consequences.

The optimal frequency for routine urine drug testing is usually left up to the provider. We recommend testing more frequently early in treatment and spacing tests out as treatment progresses. Patients who are stable and doing well probably do not need a UDS at every visit. As a general guideline, if your suspicion of drug use is so low that a positive result would surprise you, it may be worth reevaluating whether to order a UDS in the first place. See our interview with Dr. Becker in CATR May/June 2022 for a more in-depth discussion of this topic.

Order confirmatory testing

Familiarize yourself with causes of UDS false positives. Many are outlined in the “Common Causes of False Positives” table. Whenever possible, order confirmatory testing for suspicious results, especially for the more error-prone tests like amphetamines, opioids, and fentanyl. Though not perfect, confirmatory testing is vastly more reliable than UDS. Moreover, GC-MS reports provide drug levels, allowing providers to trend results over time and demonstrate abstinence if levels consistently decline.

Document carefully

If you encounter a patient with an unexpectedly positive UDS, a detailed and well-reasoned note could go a long way in protecting them from negative legal repercussions. Clarify why the test was ordered, the reliability of the test, and why you question the positive finding. See “Example Documentation of Unexpected Positive UDS” box.

CARLAT VERDICT 

Urine drug testing can be a double-edged sword in the treatment of SUDs, serving as a useful clinical tool  but possibly carrying significant legal weight. A UDS is ubiquitous and quick but can give false results, while a confirmatory test is accurate but still not entirely foolproof, in addition to being expensive and slow. As a clinician, order drug testing judiciously, utilize confirmatory testing for accuracy, and carefully document unexpected results to safeguard patients from potential legal ramifications.