The PEth Blood Test in the Security Environment: What it is; Why it is Important; and Interpretative Guidelines
William Ulwelling M.D., M.P.H., Kim Smith Ph.D., ABPP
First published: 13 July 2018 https://doi.org/10.1111/1556-4029.13874
Testing for phosphatidylethanol (PEth) is a relatively new tool for detecting and grossly quantifying a person’s use of alcohol in a variety of security, medical, and legal environments. The basic chemistry of PEth is explained with a particular focus on factors that make it highly suitable as a biomarker for alcohol use in such situations. This article meets the need for a literature review that synthesizes PEth laboratory findings and suggests updated guidelines for interpretation. Several ethanol biomarkers have been used for detection or monitoring alcohol use but have significant limitations. Based on this review, the authors propose three guidelines for evaluating PEth values: Light or no Consumption (<20 ng/mL), Significant Consumption (20–199 ng/mL), and Heavy Consumption (>200 ng/mL). These guidelines are important in employment and security environments, but also have applicability in such diverse activities as alcohol treatment programs, organ transplant decisions, and monitoring impaired medical professionals.
click here to read a summary of the article
child guard Hair testing: Exposure vs. ingestion
When a child or someone under guardianship is exposed to illegal substance abuse they often also face other coexisting obstacles to a normal life - neglect, abuse, violence, and other vulnerabilities.
Substance abuse is a disease, one that often prevents adults from doing what is in a child’s best interest. Detecting these dangerous environments is paramount to keeping the child safe. Testing with ChildGuard® can assist, where other exposure drug tests fall short. ChildGuard® is the only drug test designed to detect passive exposure to drugs, distinguishing between both native drugs and drug metabolites in hair specimens. Drug metabolites are produced in the body only if drugs have been ingested. Children in drug exposed environments are most often not drug users themselves, so drug metabolites are typically absent when a child is being tested for drug exposure.
Typical hair tests with other labs will only report a positive exposure result if drug metabolites are detected, even when the native drug is in the child’s hair specimen. ChildGuard® reports a positive result if either native drugs or drug metabolites are detected, giving much better insight about the child’s environment. ChildGuard® can provide evidence of substance use in a child’s environment for the past 3 months, and can be performed on donors of any age.
A positive ChildGuard® test result suggests that the donor has experienced one or more of the following:
• Contact with drug smoke,
• Contact with sweat or sebum (skin oil) of a drug user,
• Contact with the actual drug,
• Accidental or intentional ingestion of the drug(s).
Our forensic test for passive exposure is the first and only test of its kind. See our hair testing pages for information about specimen collection. Toxicology completed by United States Drug Testing Laboratories, Inc.
Dilute Urine Drug Screens
Avoiding a Dilute Urine Specimen
Urine samples are called DILUTE if the creatinine is less than 20mg/dl. This number is somewhat arbitrary but was chosen because most people must consume significant amounts of water to produce a specimen with a creatinine lower than 20 mg/dl. It has been noted that small muscle mass, being female, and exercise (when followed by increased water consumption) have been associated with lower urine creatinine levels.
Dilute urine drug screens are of significance because this is the most popular, easiest and least expensive ways of cheating/ masking urine drug screens. Dilution is also the method by which many over the counter urine detox cleaners work.
Since dilute urine can be used to mask the use of drugs and/or alcohol, it is imperative to try to avoid them when testing for probation, court, or other legal situations. Here are some simple guidelines to avoid providing dilute urine.
Most court, probation, diversion and/or pre-trial service personnel consider dilute specimens as positives, so following these guidelines will help to reduce producing a dilute urine specimen and reduce the risk of further legal consequences.
If dilutes specimens persist, it may necessary to discuss a different method of testing and/or getting a physical health checkup to determine possible kidney dysfunction.
UNderstanding THC levels
How to determine NEW USE vs. NO USE in urine drug screen results
Due to the increasing popularity of THC products such as waxes, sugars, and other potent concentrates, which typically range from 60-95% THC, frequent users may show positive results for upwards of 6-8 weeks. Understanding how to interpret UA results is key to determining whether your client is abstaining or continuing to use THC.
When looking at THC levels (Urine Drug Testing ONLY) to determine the pattern of use, it is important to consider the THC/ Creatinine Ratio and not the THC level alone. THC levels will fluctuate over the course of the day based on the clients’ hydration status. Morning urine is generally more concentrated than late afternoon urine, following the normal intake of daily fluids. In other words, the same client, testing at different times on the same day, would present with very different THC levels, even though the amount of THC in their system is generally the same.
The Ratio takes into consideration both the THC level and the Creatinine level and is calculated by simply dividing the two numbers. This number will be your BASELINE and will become the number by which you compare all future results to.
EXAMPLE: NO NEW/ DECREASED use of THC since baseline test on 5/17
*Results in which the Ratio continually decreases will show that the client has decreased and/or discontinued use of THC. In this example, despite the fluctuations in the THC levels, the decreasing THC/ Creatinine Ratio indicates that there has been decreased and/ or no new use of THC since the baseline test on 5/17.
EXAMPLE: NEW/ INCREASED/ SUSTAINED use of THC since baseline test on 3/22.
*The fluctuating THC/ Creatinine Ratio between testing periods in this example shows evidence of decreased, increased and sustained use of THC. If the ratio on one test, is higher than the ratio on a previous test, this means that there has been new use of THC. Interesting to note: The THC levels on the 6/3 test are considerably higher than the 5/24 test, however, based on the ratio, there was decreased use between testing periods. This is reflected in the creatinine levels of 67.4, which is urine that is significantly less concentrated than that with a creatinine level of 262.6.
In summary, the THC Level ALONE is only an indication that there is still THC present in the system. It is the THC/Creatinine Ratio that is used to determine whether new use of THC has occurred.
what is peth testing?
Phosphatidylethanol (PEth) is an abnormal phospholipid formed in cell tissues following ethanol alcohol exposure. During the metabolism process, PEth accumulates in the blood and exists as a component of the red cell membrane. Since it is formed ONLY when the body is exposed to ingested ethanol, PEth is considered a DIRECT mid to long-term alcohol biomarker, remaining detectable in the blood for up to 28 days. A positive result is an indication of intentional alcohol drinking during the 2-4 weeks prior to the collection of the blood. Additionally, the half-life of PEth is 3-5 days, therefore, one could reasonably assume PEth levels based on the individuals’ last report of use, based on an available baseline reading.
While ethyl glucuronide (EtG) urine drug testing is a sensitive and valuable assay for those individuals in treatment programs for alcohol abuse, recent studies have indicated that low level positive EtG results can be produced by certain agents like hand sanitizers and mouth wash. In contrast, the PEth assay helps to discriminate between incidental exposure and intentional alcohol ingestion, as the volume of alcohol required to trigger a positive PEth result is far above the level commonly attained by incidental exposure.
In summation, positive PEth results are a result of intentional alcohol ingestion and CANNOT be produced by incidental topical exposure to ethanol, ie.) hand sanitizer, gasoline, isopropyl alcohol prep pads, or even vodka itself.
An article published in the November 2018, Vol. 63, No. 6, Journal of Forensic Sciences named “The PEth Blood Test in the Security Environment: What it is; Why it’s Important; and Interpretive Guidelines” is a critically peer reviewed article that I rely on to understand and interpret positive PEth results. Additionally, the same article is currently the gold standard by which USDTL (United States Drug Testing Laboratory), SAMHSA (Substance Abuse & Mental Health Services Administration), and a consensus of Lab Authorities across the globe currently refer to for guidance on PEth education.
This same article refers to the Legal Valuation of PEth testing being accepted by both administrative hearings across the US, including the US 7th Circuit, where it was determined that “PEth in blood is in current use all over the world and have been accepted by professionals in this specialized world” and that “these tests are being used all over the country for family court matters as well”. According to the Texas Bar Association in 2017, “it is clear that the PEth has been judged to be meaningful in aiding court decisions”.
The interpretive guidelines outlined in the article state that: