Book:The Comprehensive Guide to Physician Office Laboratory Setup and Operation/Primary laboratory testing domains in the POL/Toxicology and pain management

2.5 Toxicology and pain management

Toxicology is the study of the effects of chemicals, elements, and other molecules on living organisms. In the CLIA-waived POL, this testing is essentially limited to drugs of abuse and the heavy metal lead (a CLIA-waived system for lithium testing called InstaRead seems to no longer be manufactured). Drug screenings in particular became more common in the first two decades of the twenty-first century, mandated not only by employers but also in some cases by the federal government. While this sort of testing holds importance inside and outside the POL, it also has been abused historically. For example, the number of POL-based drug screenings paid for by Medicare skyrocketed between 2000 and 2009 as physician offices realized they could make good money on easy testing. As such, CMS amended their rules in 2010 to prevent this type of unintended billing behavior, decreasing the financial viability of such tests for the POL.

Tangentially related is the practice of pain management, the study of how best to improve the quality of life of those living with pain. Chronic opioid therapy is one such related treatment method, though it too hasn't come without risk of abuse. Physician-owned pain management clinics or private practices offering pain management services are increasingly regulated, though those regulations neither explicitly state that urine drug tests or some other form of adherence monitoring are required, nor do they currently prohibit opioid and other drug-based therapies on patients abusing controlled substances. Despite this, "compliance monitoring has been shown to be crucial in delivering proper opioid therapy and preserving this therapy for the future," and urine drug testing is one of the major tools used in this monitoring.

2.5.1 Testing

As drugs are metabolized, they produce metabolites which show up in urine and saliva. As such, both urine- and saliva-based tests have been manufactured to make qualitative and quantitative determinations of a metabolite's presence relatively easy and accurate. Ethanol is a common legal drug in the U.S. and constitutes one of the drugs tested for in CLIA-waived tests. Note, however, that ethanol testing is not typically part of a qualitative immunoassay-based urine test; the associated metabolites ethyl glucuronide (EtG) and ethyl sulfate (EtS) may appear in urine for reasons other than direct alcohol consumption, including the ingestion of partially fermented juices and absorption through the skin of alcohol-based lotions. Since ethanol equilibrates rapidly between saliva and blood, and a saliva test is rapid and easy to administer, most CLIA-waived tests for ethanol—usually quantitative—will be saliva-based. Qualitative testing for amphetamines, cannabinoids, morphine, and many other constituents of drugs classified as drugs of abuse is typically done with relatively simple CLIA-waived urine test cups and cards. However, proper care in specimen labeling, storage, technique (including timing recommendations), and interpretation are still vital to ensure the most accurate results.

In the particular case of pain management, a simple qualitative immunoassay-based urine drug screen isn't always appropriate or accurate. Differences in metabolites and problems with accuracy come with those simplified tests. More accurate measurements may be necessary in the pain management laboratory, necessitating chromatographic tools and techniques that fall under CLIA moderate to advanced status. Given the previously mentioned fact that only 11.9 percent of all registered non-exempt POLs would be CLIA certified for such testing, this sort of advanced testing would be limited to pain management POLs willing to go through the financial and regulatory hoops involved.

For testing levels of lead in blood, the LeadCare II lead testing system remains the only CLIA-waived option.