One Third of Field Drug Test Units Give False Positives

A recent investigation into portable drug testing kits used in the United States found that 32% of the units in use were liable to give false positives, leading to a staggering 75% wrongful conviction rate.

The study was carried out by allgov.com and used results supplied by a crime lab in Houston run by James Miller – one of the few labs in the state — and indeed in the country — to test evidence even in the case of a guilty plea. It showed that hundreds of people convicted of drug possession were not actually guilty of a crime, and had instead pleaded guilty in order to receive a reduced sentence, which they saw as the best way to solve a dreadful situation.

Innocent until proven guilty?

In many states across the US, drug convictions make up approximately 10% of total arrests. In several states more than 90% of the convictions are achieved through plea deals struck by defendants and court-appointed lawyers, in order to avoid going to trial.

However, it has now surfaced that the inaccuracy of the $2 tests which police officers use to verify the illegality of a substance could be throwing up huge injustices. When the samples were checked using gas chromatography in tandem mass spectrometry (GC-MS) it was found that almost a third yielded false positive results.

The kits work by placing the sample into a sealed plastic pouch, then breaking a vial of chemicals inside the airtight vessel. The chemicals interact with the sample and will change colour if they detect the presence of an illegal substance. In addition to changing colour when it comes into contact with cocaine, a portable field kit might also give similar results when interacting with methadone, a variety of household cleaning products and any number of other substances.

However, these devices were developed back in the 1970s, at which time tighter legislation was put in place surrounding their use. Over the years, the legislation has been relaxed and the devices used more often, but the technology has not advanced.

Caution needed

The fact that many defendants strike a plea bargain leads critics to surmise that they are ultimately guilty of drug abuse and possession, albeit perhaps not on the occasion in question. While this may be true in certain cases, there are others who are simply frightened into pleading guilty because their legal team advises it, as in the sad case of Amy Albritton.

Clearly, a better system is needed. This must come in the form of improved technology to test substances, strict legislation to implement it and enhanced training courses to minimise the risk of human error in the process. Setting up a toxicology lab and testing regime is discussed in the article, High-Performance Gold Standard Toxicology Lab in just 4 months An interview with Dr Ben Davies of Healthscope Pathology on starting a NATA lab to serve the communities in South Australia.