By Pat Anson, Editor

One of the less publicized provisions in the Centers for Disease Control and Prevention’s opioid prescribing guidelines is a recommendation that doctors stop urine drug testing of patients for tetrahyrdocannabinol (THC), the psychoactive ingredient that causes the “high” for some marijuana users. The guidelines also discourage doctors from dropping patients if marijuana is detected.

Urine drug screens are conducted almost routinely by pain management physicians and other opioid prescribers for a variety of drugs, both legal and illegal.

Some doctors use a positive result for THC as an excuse to discharge patients from their practices, even in states where medical marijuana is legal.

While the CDC guidelines encourage physicians to conduct urine drug tests before starting opioid therapy and at least annually afterwards, they draw the line at THC.

“Clinicians should not test for substances for which results would not affect patient management or for which implications for patient management are unclear. For example, experts noted that there might be uncertainty about the clinical implications of a positive urine drug test for tetrahyrdocannabinol (THC).” the guidelines state.

"Clinicians should not dismiss patients from care based on a urine drug test result because this could constitute patient abandonment and could have adverse consequences for patient safety, potentially including the patient obtaining opioids from alternative sources and the clinician missing opportunities to facilitate treatment for substance use disorder."

As Pain News Network has reported, “point-of care” (POC) urine drug tests, the kind widely used in doctor’s offices, frequently giving false positive or false negative results for drugs like marijuana, oxycodone and methadone. One study found that 21% of POC tests for marijuana produced a false positive result. The test was also wrong 21% of the time when marijuana is not detected in a urine sample.

Not mentioned in the CDC guidelines is evidence that opioid overdose rates declined by nearly 25 percent in states where medical marijuana was legalized.

"We applaud the CDC's reasoned approach to the use of urine testing and its drawbacks when used on pain patients," said Ellen Komp, Deputy Director of California NORML. "Considering that opioid overdose deaths are significantly lower in states with medical marijuana programs, we are sorry the agency apparently didn't read the letter Elizabeth Warren recently sent to its chief calling for marijuana legalization as a means of dealing with the problem of opiate overdose."

That letter by Sen. Warren encouraged the CDC to adopt the guidelines and its restrictive approach to opioids “as soon as possible,” but also encouraged the agency to further study the impact legalization of medical and recreational marijuana could have on opioid overdose deaths.

The annual cost of drug testing in pain management is estimated at $2 billion per year. While POC tests are relatively cheap, more expensive laboratory testing can cost thousands of dollars and is often not covered by insurance.