Doctor Defends Use of Urine Drug Tests

By Pat Anson, Editor

A prominent pain doctor is disputing reports that a widely used urine drug test often gives faulty results.

“They are reasonably reliable and highly cost effective for use in a pain management practice. I would strongly recommend the practitioners use this,” said Laxmaiah Manchikanti, MD, chairman and CEO of the American Society of Interventional Pain Physicians.



Dr. Manchikanti, who is medical director of a pain clinic in Paducah, Kentucky, was the lead author of a study published in the journal Pain Physician in 2011, which looked at the reliability of immunoassay “point-of-care” (POC) tests. The urine tests are inexpensive and give immediate results, and doctors often use them to monitor their patients for opioid or illicit drug use.

“The UDT (urine drug test) with immunoassay in an office setting is appropriate, convenient and cost effective. Compared with laboratory testing for opioids and illicit drugs, immunoassay office testing had high specificity and agreement,” Manchikanti's study found.

Pain News Network recently reported on the results of a second study conducted by Millennium Health, a San Diego-based drug testing laboratory, which found that POC tests were wrong about half the time – frequently giving false positive and false negatives results for drugs like marijuana and oxycodone. The Millennium study advocates the use of chromatography-mass-spectrometry – a more complex laboratory test that costs thousands of dollars – to confirm POC test results.

Following the advice from companies in reference to numerous expensive tests and also income generating avenues will only lead to time in the slammer and will not improve patient care at all,” said Manchikanti.

“(The) Millennium study is performed by the company which makes a living by testing. The more samples that are sent to them, the better off they are. Further, they are not even a practical setting. From our practice we send approximately only 2% of the samples for confirmation testing. Even then, the patients can’t pay their bills.”

Manchikanti’s study found false negative and false positive rates for POC tests that were far below the rates reported by Millennium.

For example, Millennium’s false positive rate for oxycodone was 41.3 percent. For Manchikanti, it was only 7.7 percent.

Millennium’s false positive rate for marijuana was 21.3 percent. For Manchikanti, it was just 2 percent.

There were discrepancies between the two studies for several other drugs, including methadone, cocaine and methamphetamine.

Millennium Sponsored Both Studies

How could two studies come to such different conclusions?

There were some differences in their design. Urine samples in the Millennium study came from nearly 4,300 patients in addiction treatment clinics, while the urine samples in Manchikanti’s study came from 1,000 patients in pain management programs. Millennium maintains the patients in its study were younger and more likely to be drug users.

Ironically, the laboratory tests for both studies were conducted by Millennium – which collected samples and provided chromatography-mass-spectrometry testing at no cost to Manchikanti. Millennium is identified as the “sponsor” of Manchikanti’s study, but he says the company had “no influence or interference” in his and his three co-authors’ findings.

We had our agreement in the beginning itself that they will not be involved in any way in writing the manuscript or publishing the results. Consequently, they really did not have much input into the publication. The publication was as it is and without any bias from the industry,” Manchikanti wrote in an email to Pain News Network.

Millennium’s study, which was published last year in the Journal of Opioid Management, had six co-authors. All but one were employees of the company. The lone exception is a pain management doctor who frequently testifies as a legal expert for Millennium in court cases.

A source with broad experience in the drug testing industry told Pain News Network the data in Millennium’s study was “skewed toward exaggeration.”

“It does not surprise me that Millennium would show a high rate of inconsistencies with the POC test. Remember, their business is to sell confirmation testing, so they will skew the way they present data to try to influence the market to do more confirmation testing.  In most cases, that’s how it works in any study conducted or funded by a device or pharmaceutical company,” the source said.

Millennium bristles at the notion that its study was biased.

“Millennium Health strongly disagrees with the characterization… that the study was skewed or biased in any way,” the company said in a statement to Pain News Network.

“The study was accepted and published by a well-respected, peer-reviewed publication. Millennium Research Institute is committed to the highest ethical and research science standards, and we stand by the results of our study. The study was based on random samples from addiction treatment clients. The data clearly indicated that immunoassay, or point-of-care, tests have a high rate of false positives and false negatives when used to screen patients for illicit drug use.

“Millennium is committed to providing data that helps clinicians evaluate the best course of treatment for patients with pain and addiction issues. Millennium Health performs only the tests ordered by clinicians.”

In recent years a growing number of doctors who treat addicts and pain patients have required them to submit to drug tests. The competition between Millennium and other laboratories for this business is intense. According to one estimate, drug testing has grown into a lucrative $4 billion dollar a year industry.

But Manchikanti maintains that a single inexpensive urine test that costs about $20 is often the only one that’s needed.

“If a proper (patient) history is provided which matches with the test, there is no need for further testing,” he said.