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August 25, 2022
Chronic non-cancer pain is a serious health problem. While the long-term effects of treating chronic non-cancer pain with opioid drugs is not clear, prescription opioid usage has increased over the past decade to help treat chronic pain. The misuse of prescription opioids has increased dramatically over the past decade. A significant problem for health care providers is the need to manage pain and avoid opioid misuse. The prescribing of these drugs requires additional methods to detect misuse. There are many tools that can be used to detect opioid misuse and abuse, including prescription drug monitoring programs, drug testing, and question-based screening tools. It has been widely recommended that urine drug testing be used to identify opioid abuse and misuse during chronic pain treatment. This method is also often used in clinical settings to screen patients for drug dependence, such as those with behavioral disorders or other signs and symptoms. It is important to correctly interpret the testing as it could be the basis for treatment decisions, criminal prosecution or eligibility for organ transplant.
We want to bring attention to opioid drug testing given all the current issues Americans face regarding the opioid epidemic. This is a topic that continues to evolve with increased opioid use. We will discuss the importance of testing methods and how they impact the interpretation of clinical results.
The workplace-based approaches have been used in traditional drug screening methods for clinical medicine. While we will be focused on opioids, similar testing is possible for many substances. Two levels of testing are used in the traditional testing system. The first tier is designed to quickly screen for opioids large numbers of specimens. The second tier is performed with highly specific methods, such as liquid chromatography and mass spectrometry. This confirms the screening result. Confirmatory testing must be performed in both the workplace and forensic setting. The latter follows the Substance Abuse & Mental Health Services Administration (SAMHSA), testing guidelines. Because confirmatory results may not be available on the same day and are less likely to impact clinical decision-making, hospitals that perform urine drug testing for clinical purposes might not use this second level of testing.
Any testing program’s initial screening is crucial. Workplace opioid testing seeks to detect illicit drug use in a population that has a low rate of opioid abuse. The prevalence of drug use is higher in the clinical setting because patients are selected based on clinical suspicion or prescription of opioid drugs. In the clinical setting, the purpose of testing might be different. The goal of testing is to detect drug diversion. The utility of testing is affected by the differences in testing goals and prevalence. In clinical settings, the test’s effectiveness can be increased by changing the cutoff concentration used to determine a positive or a negative result. The cutoff concentration for positive opioid screens in clinical laboratories is still 300 ng/mL. However, this cutoff concentration has not been thoroughly evaluated in all clinical settings where it is used. This threshold was developed for adults and may not work well in children with less concentrated urine. In pain medicine, lower thresholds are recommended. In most clinical settings, the federally mandated threshold of 2,000 ng/mL for workplace testing (described below) is unlikely to be appropriate.
Screening tests for opioids are not able to detect all drugs, which is often misunderstood. Opiate immunoassays that use an antigen/antibody interaction to detect opioid drugs typically use morphine for a single calibrator drug. This allows them to determine the threshold for determining whether a test result is “positive” or negative. Because of the limited cross-reactivity between antibodies and the variety of opioid drugs, urine samples containing multiple drugs could be missed by opiate immunoassays.
The use of drug testing for opioid drugs by health care professionals is an important tool to evaluate compliance with opioid treatment and misuse. However, it is not a perfect diagnostic test. UDT cannot identify all instances of opioid misuse or use. UDT’s accuracy is hard to determine as it is used often as a standard for other methods of misuse detection or risk assessment. A study of chronic pain patients found that 88 percent of those who reported using opioids were positive on UDT. However, the study also showed that many patients do not report drug use, particularly illicit drugs.
It will depend on the situation in which testing is performed. Clinicians will usually only have confirmed immunoassay screening results in clinical settings, especially where it is necessary to make urgent decisions. It can take up to 24 hours for confirmatory testing, depending on the lab’s work flow. The ideal method of testing in pain medicine, which is rapidly growing, is not well understood. While some advocate random, sporadic testing for high-risk patients, others favor universal testing every patient visit. Prospective clinical trials have not evaluated either approach. This area of testing needs more outcome-based research. UDT can be combined with other screening tools, such as the behavioral assessment tool, to achieve its greatest efficiency.
Keystone Laboratories, a CAP-accredited North Carolina licensed laboratory and CLIA-licensed lab, is committed to helping you make important decisions that impact the safety and health of your patients with greater confidence. Clients in 48 states can get prescription drug and substance abuse recovery monitoring, specialized testing, workplace drug testing, screening, and program management services from Keystone. Contact Keystone Laboratories today to receive the industry-leading laboratory testing services!