Like many stoners across the US, one of my favorite shows is the Colbert Report, I try to watch it pretty regularly despite my lack of cable. A story from Colbert’s popular “Threat Down” segment piqued my interest while catching up on some missed episodes the other night. In the segment Stephen reported on a story involving newborn babies testing positive for the principal psychoactive component of cannabis, THC, during infant drug screening. Unfortunately Stephen makes a gaff* stating that the cause of the false positives was baby wash that actually “contain[s] THC”. This is simply false, the true culprit appears to actually be unrelated chemicals in the soap and no detectable amounts of THC in the soap were reported.
For those unfamiliar with the practice of infant drug screening I’ll explain a little bit. In many places infant drug testing is common, though generally it is limited to at-risk mothers and babies such as those with little record of prenatal care and is much more accurate than relying on self-reporting alone. Drug testing is fraught with legal and personal liberty issues but the justification of needing accurate individual and epidemiological data to make rational health decisions should also be understood. While a false positive on an infant drug screen is not likely to end in the child being taken from the parents, it can result in unnecessary investigations by social services and plenty of hassle making accurate screening important.
With this in mind investigators at the University of North Carolina routinely conduct studies looking at potential cross-reactions between various therapeutic drugs and the immunoassay-based screening used in their lab, this is often in response to observations or queries. In July of 2011 investigators at the University of North Carolina became aware of a number of apparent false positives for cannabinoids in infant drug screening by way of one such query from the nursery staff. In these cases while the urine of some babies tested positive for cannabinoids, often the meconium would not. After some investigation the researchers found that,
Specifically, there was considerable variation between nursing staff in cleansing the newborn prior to collection and in collecting the samples: Some placed cotton balls or gauze within the diaper, others used collection devices, while others turned diapers inside-out. These factors, in conjunction with a higher screen-to confirmation discrepancy rate than typically seen in the adult population, implied an interference unique to the nursery. Therefore, we sought to examine all nursery-specific products that could potentially come in contact with newborn urine samples to determine any potential effect on THC screening.
The researchers then tested a number of products including cotton balls, baby wipes, and a variety of baby washes and soaps for cross-reactivity. The results of their study found that, “four out of seven commercial baby soaps caused assay interference sufficient to yield a positive screen result”. The research also found that, “evaluation of polyquaternium 11, cocamidopropyl betaine, and a mixture of PEG 80, sorbitan laurate, and cocamidopropyl betaine all showed strong reactivity in the THC assay, while sodium lauryl sulfate showed no reactivity.”
In discussing their findings the researchers noted,
These findings were interesting because Mikkelsen, et al. and Uebel, et al. independently found hand soaps to be an effective means of thwarting detection of illicit drug by producing false negative screening results when small amounts were added to urine in the setting of workplace drug testing. This approach to circumvent detection has prevailed within the workplace setting and is one of the reasons urine pH continues to be measured. Interestingly, Warner reported the potential for Joy liquid detergent to cause both false negative as well as false positive cannabinoid results depending on the immunoassay used.
The authors then conclude their study with the recommendation that,
all positive newborn urine and meconium screening results undergo reflex confirmatory testing using a more sensitive and specific method such as GC/MS or LC tandem MS. We also suggest that this is an area in which improved assays, both screening and confirmatory, are needed that can help clinical laboratories meet the challenges unique to the application of drug testing within this population.
So yes, it does appear that baby soaps are causing at least some false positives for THC in infant drug screening, though it is not because the soaps contain any measurable amounts of THC. While this is a legitimate concern for reasons stated above, there is no need to worry about your baby getting high from routine bathing…just keep the “bath salts” out of reach.
*Ok, maybe I shouldn’t be so worried about the accuracy of a parody news program, but considering polls revealing that a significant percentage of young people use such shows as primary news sources it is something to at least consider. I should also note that Stephen was repeating the words of another anchor and was certainly not the first one to get it wrong.