Today we are going to discuss the different specimen types that can be used to test for drugs. We do offer testing for all the specimen types that I will cover. It is helpful to know what to expect from each specimen type in regard to window of detection (both onset and outset), susceptibility to adulteration, collection woes, and general benefits or shortcomings. So, take a few minutes to read and decide for yourself if you are testing the specimen type that works best for your program or facility.
Blood is probably one of our least favorite specimen types. Firstly, it is relatively hard to collect, requiring a trained medical practitioner at least. The second reason it is at the bottom of the list is its short window of detection; substances can only be detected when they are in the bloodstream (while the donor is under the influence). This is actually a plus when we are talking about workplace injuries (as an example) when we want to find out if someone is impaired at the time, but we (collectively) are more likely to be concerned with recent prior drug use. Lastly, there are essentially no onsite/instant tests for drugs of abuse that use blood as a specimen type. However, on the plus side, it is impossible to adulterate a blood specimen.
Hair follicle specimen are not as difficult to collect as blood; there is no medical knowledge necessary. Hair testing also has no gender concerns with witnessing collection. As with blood, however, it is only available as a laboratory test. Another shortcoming with hair is the limited number of drugs that are being tested (only tests: AMP, COC, THC, OPI, OXY, PCP). While hair provides a very long window of detection – detecting drugs for up to 90 day after use – it also has a long onset, meaning drugs will not begin to be detected until about 7 days after use. As for adulteration, there are many products on the internet that claim to “detoxify” your hair to remove any drugs that may be present, but I have not found any evidence that these products are effective.
Sweat patch testing is a relatively new offering and it is somewhat unique in its window of detection. The patch is typically worn for 10 days (or more), and drugs take about 2-3 days to come to the surface of the skin, so if positive it would most likely be from use 2-3 days before the patch was applied, or used in the first 7 (out of 10) days the patch was worn. The downside here is that if a participant knows the patch is coming off Monday, they could use drugs Saturday or Sunday without the use being detected. It is a very simple specimen to collect with no gender concerns as it is placed on the arm. There is no known method of adulteration for the sweat patch. As with hair, it is only available as a laboratory test, and also like hair, it is a limited range of drugs that are detected, adding only MET to the list of detectable hair substances.
This one is sort of the oddball here; it is not a test for drug use, it is a test to see what substance a person may have in their possession. It will also test surfaces for possible contamination by drugs (i.e. a person’s desktop or computer keyboard). This is most often used by law enforcement in the field (it is sometimes called a “field test”), perhaps testing a baggie found on a person or in their vehicle. It can also be helpful for corrections or any other residential facility where drug residue might be found in someone’s cell, or other space where only a limited number of people might have access. Much like a drug test, however, it must be a “target” substance – in other words you must use the right test to get a positive or negative hit on that particular substance. Since so many illicit (or misused) drugs can be a “white powder”, you might not happen to have tested for the correct white powder!
Saliva testing has become more popular as the accuracy and precision of the instant/onsite saliva tests have improved immensely over the years. One appeal of saliva testing is that there are no gender concerns for witnessed collections, not even a bathroom is needed; it is also a fairly simple collection and testing procedure. However, while it is much easier to collect (and less invasive) than blood, it shares the same limitation of the window of detection; drugs will not be detectable in saliva for more than 24 hours after use. As with blood, this window of detection makes the most sense when impaired driving and workplace injuries are the concern.
Urine remains our favorite specimen type. While there are gender concerns for witnessed collections, and adulteration is more possible than with other specimen types. The window of detection, the huge number of substances able to be tested, and relatively lower cost still outweigh the negatives. Witnessed collections can be a challenge, but not one too challenging to be more than a mild inconvenience in most cases. Adulteration is a concern, but modern adulterant testing is thorough enough to be an excellent deterrent. On the other hand, the window of detection shows recent use, going back days (or weeks, depending on the substance), which fits almost universally with what we are trying to determine. There are instant tests available for more than 25 drugs of abuse and lab tests available for more than 40; this is a huge improvement over any of the other specimen types listed. Lastly, the cost is going to be the lowest out of all the specimen types, making it more feasible to follow a regular testing schedule.
Thanks for this information. I am new in this testing arena with no or very little prior experience.
Insightful as always. Thank you, Eric.