Ed. Note: Chris Halkides has been kind enough to try to make us lawyers smarter by dumbing down science enough that we have a small chance of understanding how it’s being used to wrongfully convict and, in some cases, execute defendants. Chris graduated from the University of Wisconsin-Madison with a Ph.D. in biochemistry, and teaches biochemistry, organic chemistry, and forensic chemistry at the University of North Carolina, Wilmington.

When we think of screening tests for drugs, roadside or airport seizures come to mind. However, a great deal of testing is also performed involving incarcerated individuals, both for consumed and seized drugs. In January, the New York State Office of the Inspector General issued a report on a scandal involving the Department of Corrections and Community Supervision (DOCCS), which had been using tests from the Microgenics Corporation.

The kernel of the problem is that presumptive tests produce false positives in the presence of other licit or illicit substances. When a positive result is observed, the prisoner may be confined to a cell (sometimes in solitary), or he or she may lose privileges such as access to rehabilitation programs or visitation rights. One such prisoner who challenged a positive presumptive test felt overwhelmed by the complexity of the scientific literature of cross-reacting substances.

The presumptive testing in question was for synthetic opioid buphrenorphine or cannabinoids. Microgenics’ Buphrenorphine II test is likely to yield false positive results for Tylenol plus codeine, the cough suppressant Dextromethorphan, and Oxycodone. Testing for cannabinoids may produce a false positive for certain soap-based products, the cholesterol-lowering medication Atorvastatin, or the antiretroviral compound Efavirenz (EFV). When a xenobiotic is consumed, it may be oxidized, joined to glucuronic acid to become a glucuronide, or metabolized in another way before being excreted in urine. EFV-glucuronide, but not EFV itself, produces a false positive in at least one screening test for cannabinoids. EFV and its oxidized form produce false positives for benzodiazepines in some tests. There are indications that a metabolite of the antiacid Omeprazole will produce a false positive in Microgenics’ Buprenorphine II test. The substances producing false positive will almost certainly depend upon the manufacturer.

The obvious solution to the problem of false positives in screening tests is to perform confirmatory tests using a more specific test (a test yielding fewer false positives), something that Microgenics’ own product literature indicated. The report stated, “DOCCS also committed various administrative failures…[including a failure] to consistently consult medical staff on possible cross-reacting drugs—actions required by policy. Also, the investigation found DOCCS did not adequately train drug-testing staff and hearing officers on the drug tests and instruments.”

When a positive result was obtained, DOCCS simply ran the same test over again. This policy was based on Peranzo et al. v. Coughlin, a 1985 class action suit.

The court in Peranzo did not consider the possible presence of cross-reacting substances in urine samples provided by incarcerated individuals for drug tests. This fact makes DOCCS’ reliance on Peranzo to forgo confirmatory testing questionable…However, the Inspector General’s investigation found that DOCCS’ proficiency testing was not conducted with actual urine samples but instead with samples of a solution that either contained or did not contain a target drug. Notably, these samples were free of any possible cross-reacting substances.

Performing the same test over again might catch an operator error, but it does nothing to address the inherent limitations of presumptive testing. Peranzo was clearly an erroneous decision.

Nor was Microgenics blameless. A corporate representative informed an inmate that the test was 99.9% accurate. Presumptive tests are judged on the basis of specificity and sensitivity; what accuracy means is unclear. Perhaps this was one of the “misleading and inconsistent statements during disciplinary hearings” that Inspector General Lucy Lang had in mind. This report stated,

Microgenics also failed to disclose to DOCCS that internal research had found that some common medications prescribed to incarcerated individuals and other common substances ingested by them might cross-react with its test reagents and cause false positive results when using the Buprenorphine II test…Moreover, the investigation found that Microgenics Sales Representative Collum instructed company representatives not to discuss confirmatory testing during DOCCS’ hearings.

Although it is likely that some of the positive results were false, it is difficult to assess how many were: “In a limited review of six positive samples using Microgenics’ tests, two outside laboratories later determined four of the six positive test results were incorrect.” One inmate who tested positive for synthetic cannabinoids was put into a special housing unit (solitary confinement for 23 hours per day), then tested positive again.  Either the result was a false positive, or SHU is not secure.

DOCCS has apparently corrected one problem: “Positive results from these preliminary screening tests are then tested using a more specific alternative method: gas chromatography – mass spectrometry (GC-MS) and/or liquid chromatography – tandem mass spectrometry (LC-MS/MS), by Cordant Health Solutions.” Mass spectrometry can examine both the mass of a compound and the masses of its fragments under controlled decomposition; it generally produces a substantial amount of information toward identifying a compound. Chromatography typically provides one additional piece of information, and the combination of the two techniques is frequently used in clinical and forensic work.

For Further Reading

Saitman A et al. 2014 J. Analytical Toxicology 38:387-396. doi:10.1093/jat/bku075
https://academic.oup.com/jat/article/38/7/387/2798054