Substance Use Monitoring Plans
by Tom Horvath, PhD
There are many occupations considered to be safety-sensitive. The industries from which they are drawn include healthcare, transportation, and construction. Specific occupations include physicians, airline pilots, and heavy equipment operators. When these individuals have their substance use monitored (often because of recent substance problems), what principles should guide the creation of the monitoring plan? Let us focus on alcohol, because it may be the most common substance monitored.
There are many methods to monitor alcohol use. They differ according to the timeframe they observe, their accuracy (will they miss use that occurred?), whether they assess the substance itself or a metabolite, the convenience of use (e.g., including how far one must go to get tested, how much privacy is lost), cost, and other factors. For alcohol, common methods include:
Blood test: directly measures alcohol in the blood, is positive only for the hours one still has a “blood alcohol level,” often used after DUI.
Breath test: directly measures alcohol in the breath, also is positive (roughly) for the hours one still has a “blood alcohol level,” often used after DUI. Inexpensive portable breathalyzers are available which can be used multiple times per day, when “continuous monitoring” is desired.
Urine testing: measures the metabolite ethyl glucuronide, EtG, in urine, is positive for 48-72 hours after drinking. This method is widely used. The most rigorous form is the observed sample (an observer is in the bathroom when the sample is collected).
PEth blood test: measures the metabolite phosphatidylethanol, can be positive for up to several weeks, the length of detection is dependent on the volume of alcohol consumed, blood could be from a finger prick or a blood draw.
Hair testing, for EtG, if 1.5 inches of hair from the head is available, can detect for 3 months. The length of detection for other body hair is not clearly established. This method would not be suitable at the beginning of monitoring because it would likely begin too soon. For instance, if your alcohol incident occurred March 1st, and monitoring begin April 1, the hair test would assess alcohol use in January, February, and March, when monitoring was needed only from March 2 on.
Ankle or wrist “bracelet:” measures alcohol in perspiration (sweat), can be positive within minutes of drinking, and thus provides real-time monitoring. Regularly used in criminal justice settings. The ankle bracelet is challenging to wear. It cannot be immersed in water. It is bulky and hard to conceal. The skin underneath may become inflamed. The ankle bracelet is typically installed by a technician for weeks or months and must be removed by the technician. The wrist bracelet is more flexible but is not yet well-known or widely used. Evidence about its effectiveness is still more limited.
Sweat patch: Similar to the bracelet. It is applied and removed at the lab. It is not as widely available as other methods. It could be replaced every 7-30 days. It could replace one of the other methods in the plans proposed below.
Fingernail or toenail testing: measures EtG, can detect alcohol for 3-6 months or longer depending on the length of the nail. This method would not be suitable at the beginning of monitoring because it would likely begin too soon.
Saliva testing: Saliva is another option for short-term detection, but it has so far appeared not to be widely used. It detects alcohol directly in saliva. The detection window is similar to blood and breath testing. It is not as invasive as blood testing and does not require a trip to the bathroom.
A monitoring plan needs to consider validity, timeliness, completeness, and convenience. The plans proposed below are suitable for individuals who continue to work and are not under the jurisdiction of the criminal justice system.
Timeliness means that if there is drinking it is detected quickly, not weeks or monthly later. Completeness means that if there is drinking it will be detected. Convenience and cost to the individual being monitored are also important because we are aiming to help move them past their substance problems. Dramatically increasing their stress level (which monitoring will do to some extent unavoidably) is counterproductive. It is also possible that the individual is to a significant extent falsely accused. In that case a highly demanding monitoring scheme is unfair.
The substance use monitoring plans proposed here are all scheduled. It is common, however, for individuals to be placed on random monitoring. There are at least two problems with random monitoring. 1) Drinking could occur and not be detected. Because the individual who might be genuinely struggling with not drinking will figure out that drinking might not be detected, the situation can increase their craving. This is counterproductive to the larger goal of preserving this individual’s contribution to society. 2) Calling in early every day, to find out whether testing is needed that day, is disruptive to someone’s life and counterproductive to helping them build up a new way of living.
Validity can be determined by using two methods simultaneously. Initially only short-term methods are applicable. PEth, hair, and nail testing look back too far typically. An initial monitoring plan could be a breathalyzer (3-4 times per day), and urine testing 2-4 times per week. If high rigor is required 4 breathalyzer readings per day, and urine testing Monday, Wed, Friday, and Saturday would provide it. However, 3 breathalyzer readings per day (upon awakening, late afternoon, upon bedtime) and Monday, Thursday, and Saturday urine testing, particularly if someone worked around others who could observe problems if they occurred, would usually be sufficient. Because there can be false positive results for the breathalyzer readings, urine testing (which I presume to be more reliable) can validate that in fact drinking did or did not occur.
Breathalyzers that do not require a test during a specific time window are typically easier to work with and significantly reduce stress on the user. Because the breathalyzer is backed up by another method, the timing of the breathalyzer reading is less significant. This approach assumes that awakening and bedtime will always be a time for readings, with one or more mid-day readings more flexibly timed.
After several weeks the PEth test will become negative (one or more tests might be needed to reach this state). PEth could then replace the urine testing. The breathalyzer, which is relatively convenient because it does not require going anywhere, can continue throughout the monitoring period. This approach assumes the breathalyzer itself is serviced and validated regularly. The breathalyzer continues to provide timely evidence, while the other method provides completeness.
In about 3 months a hair test can replace the PEth test, requiring even fewer trips for testing. PEth tests should continue until there is a negative hair test. In a highly rigorous plan, hair testing could occur once every month or two, and then possibly decrease to once every 3 months. If the interval is less than 3 months, the hair tests also validate themselves.
If someone has done well (all negative tests) for perhaps a year or more, the hair testing interval could be relaxed to every 3 months, provided the breathalyzer continues. Monitoring may be valuable for years, especially in a case where the substance problems are well established and were substantial.
Unfortunately, it appears that in the US the emphasis in these situations has been on treatment, rather than monitoring. If a rigorous substance monitoring plan is established, requiring treatment in addition is, in my opinion, unnecessary. If keeping one’s hard-earned job is not motivating enough to abstain, it is unlikely that treatment will identify motivations that would be stronger.
Liked this article on substance use monitoring? You might also be interested in: How Some Physicians with Substance Problems Get Mistreated