Defending clients in court from marijuana urinalysis “evidence” with science

[Or how your donations to NORML helped a Los Angeles woman avoid five months in a cage after failing nine consecutive urine screens for marijuana while on probation. -- "R"R]

At NORML’s Aspen Legal Seminar this past June I presented on the topic of cannabis pharmacokinetics and explained how an understanding RE: the science surrounding the metabolism and absorption of cannabinoids could be a valuable tool for defense attorneys. Recently I put my theoretical knowledge into practice as an expert witness in a federal evidentiary hearing in L.A. federal court.

At issue: defendant was under three years federal probation (probation period to expire on 8/13/09); defendant had a string of NINE consecutive failed UAs for carboxy THC beginning on 10/27/08 running through 1/08/2009. On four of the nine tests, defendant’s carboxy THC levels were HIGHER than they had been on the previous test. When the samples were normalized, defendant still failed all nine tests. Feds were willing to let the 10/27/08 test slide, as defendant showed a medical marijuana recommendation, but considered all eight positive tests thereafter to be evidence of new/continued use and a probation violation. Defendant alleged she had NOT used cannabis since 10/27/08 and that all the the positive tests since that time were residual (evidence of the use prior to 10/27/08). Feds brought in a toxicologist with 39 years experience who alleged that the string of positive tests as well as the spikes in the defendant’s test results could “absolutely not” be from residual use and instead were indicative of new drug use. Feds asked for 5 months prison time and additional three years probation.

That’s where I came in.
I was initially brought in by the L.A. federal public defenders office as a consultant to this case to explain the facts surrounding carboxy THC, half-life, trends in detection, etc. During this consulting I presented the defenders office with documented evidence that:

1) Carboxy THC is an inactive, lipid soluble metabolite with a slow excretion pattern. Clinical studies have documented that chronic users who have abstained from the drug may test positive for levels of carboxy THC metabolites for durations of time ranging from one month to 100+ days.

2) Because of this variable and long range of detection, there is a consensus in the scientific literature that the detection of presence of carboxy THC in urine, regardless of quantity, is not an accurate indicator of the time of past cannabis exposure.

3) Studies have documented that carboxy THC levels can periodically spike in urine during the terminal elimination phase regardless of the re-initiation of cannabis use. Researchers have commented that this phenomena is to be expected with the persistence of lipid soluble metabolite, and acknowledge that this phenomenon “makes it problematic to determine whether positive results are indicative of new drug use or reflective of previous cannabis exposure,” and “might tend to confuse the proper interpretation of results.”

Three days before the hearing the public defender asked me if I would fly to L.A. and take the stand to present this evidence and challenge the state’s toxicologist’s testimony. I agreed to do so, saying I would elaborate on the findings stated above, and not speculate on the defendant’s actual test results. The attorney said that the state only had to show a preponderance of the evidence (51%) in support of the allegation that her client was still using cannabis, and that chances are we would lose regardless of whatever evidence we presented.

We presented roughly eight separate scientific studies to the judge and discussed them at length in court. We even presented a chart illustrating how THC-COOH levels rise and fall irrespective of use during the terminal elimination phase. The state objected vehemently to my inclusion as an expert, and tried to argue that normalized samples (normalization is a fairly new technology) do not rise and fall in a manner similar to non-normalized samples. This statement, like most everything else they had to say, is false, and fortunately I had the studies with me to prove it.

The judge ruled on the case three days later and to the disbelief of the prosecution, she determined that the state had NOT met its 51% burden to establish that the defendant had continued to use cannabis while on probation — despite the NINE positive tests! She rejected the state’s demand for prison time and additional probation. The defendant will now complete her probation, as scheduled, on 8/13/09.

The public defender was ecstatic and now wants to similarly challenge all of her clients’ alleged ‘probation violations.’ She said that she had never thought there was even a chance that attorneys could successfully challenge a positive UA for cannabis — much less a series of them. (Clearly the state didn’t think it was possible either, as their expert’s arrogance and black-and-white testimony did them no favors.) I was thrilled to be able to assist her both as an consultant and as a witness, but even more thrilled to see my understanding of the cannabis-science and theory be put successfully into practice.

In short, a little understanding of the science can go a long way.

If folks weren’t in Aspen and would like a copy of my ppt presentation, feel free to contact me off-list [at paul'at'norml.org]