Testing for PPX and TCA: Is it Necessary?

Testing for PPX and TCA: Is it Necessary?

Today’s subject was sparked from a conversation that our sales consultants have fairly regularly. Usually this comes up in the context of us pressing to find out why a facility is using the specific tests that they are using. The answer we get more than any other is some variant of, “it’s just the way we’ve always done it.” If you’ve had any conversations with our sales team, you know they won’t simply let that answer stand alone. It is always our mission to understand the needs of each facility we work with, but sometimes this can entail explaining why some of the thought processes behind those needs might be misguided, outdated, or missing crucial bits of information.

For example, when inquiring why a facility is not testing for Fentanyl, when it is clearly the most concerning drug of abuse, we will often hear the previously mentioned, “it’s just the way we’ve always done it”, or, specific to Fentanyl, “we assumed that this would be detected on our Opiate panel”. This covers all three of the thought processes I described.

However, for this blog post, we are going to focus on the other side of this coin, substances that people have been testing for that may or may not be necessary. Keep in mind, I will never fault anyone for playing it safe and testing for everything that they can, but this doesn’t always work for facilities that need to keep costs down. I always recommend that people find a happy medium, and keeping our clients informed about substances that are of the highest concern at the time is incredibly important in helping such facilities try and find that happy medium.

Today we are going to look at Propoxyphene (PPX) and Tricyclic Antidepressants (TCA) with a nod to a couple of honorable mentions in Barbiturates (BAR) and Phencyclidine (PCP).

First, Propoxyphene, more commonly known by its brand names, Darvon and Darvocet, is a mild Opioid pain reliever. It dates back to 1954 and was developed, like most Opioids, as an attempt to create a non-addictive pain medication. Spoiler alert, it was still addictive! Being that it was a mild Opioid, it did have a slightly lower risk of addiction, but it was neither non-addictive nor totally safe, as such, this medication has been taken off the shelves in the US since 2010. Most other First World countries follow suit shortly thereafter. While it is still prescribed in other countries, albeit infrequently, it is not completely gone from the world. However, with many more commonly prescribed, and therefore more readily available Opioids, I have never in my 20+ years heard of a Propoxyphene positive result, nor any facilities having concerns with its misuse.

Next up is Tricyclic Antidepressants. Tricyclic Antidepressants are a class of antidepressants characterized by their chemical structure, which contains three rings of atoms. TCAs were also developed in the early 1950s during the early days of psychopharmacology (psychopharmacology being medications to treat mental disorders). TCAs are typically classified as, “mood elevators”, and the most commonly known is probably Elavil (Amitriptyline). These medications have not been pulled from shelves like Propoxyphene, but they are rarely prescribed these days in favor of the more modern class of antidepressants, such as SSRIs (Prozac and Celexa), SNRIs (Cymbalta and Effexor), and NRIs (Wellbutrin). Near obscurity aside, according to the US government classification of psychiatric medications, “TCAs are non-abusable”. While in slightly higher demand than testing for Propoxyphene, TCAs can be a good place to cut back on if you are trying to keep costs down.

Honorable mentions: Barbiturates (BAR) and Phencyclidine (PCP).

Please do not interpret this as my advising not to bother, or that you don’t need to test for these, but I wanted to include this in an attempt to point out how uncommon these substances have become in terms of drugs of abuse. Barbiturates have long since been replaced in most cases with Benzodiazepines (especially for sedation). However, we do see a small number of prescription medications that contain them. Fioricet, for example, is a common medication prescribed for migraines.

If you are testing BAR, I am going to guess that you probably have never seen a positive result. To a lesser extent than BAR is PCP. This dissociative anesthetic was used medically from 1956 to 1965 (1978 for veterinary medicine), until discontinued due to high rates of negative side effects. We typically see the better tolerated, Ketamine (KET), being used for anesthetic purposes in its place. While we do sometimes hear about geographic pockets of the country where this substance pops up from time to time, it is not nearly as widespread as it once was.

In summary, do not take this article as the final word on what tests are best for you or your facility to use, but take this to open up a conversation about whether or not, what you are testing for is really what you need to test for, or if it is just the way you’ve always done things.


CLIA Waived or Forensic Use Only: What You Need to Know

CLIA Waived or Forensic Use Only: What You Need to Know

What You Need to Know…

Something you may have noticed while browsing our product catalogs and/or listings is that some of the tests have a designation of “CLIA Waived”, while others are designated as “FUO”. What do these two designations refer to, and how does it affect you? Let us look a little deeper and find out.


For the pure definitions, CLIA Waived refers to both “CLIA” – an acronym for Clinical Laboratory Improvement Amendments – and “Waived” – the complexity rating of the test in question. As for “FUO”, this is an acronym for Forensic Use Only. Of course, this still doesn’t really clarify anything, so let us continue.


With the goal of ensuring that “laboratory” testing of human specimens provide accurate, reliable, and timely patient test results, no matter where the test is performed, the Clinical Laboratory Improvement Amendments were passed in 1988. Almost all medical diagnostic device or service, under the purview of the FDA (Food & Drug Administration) and CMS (Centers for Medicare & Medicaid Services) and following the guidance of CLIA is rated based on the complexity of the test. In this context, complexity refers to the ease of an individual to collect the specimen, perform the test, and interpret the results with as little room for error as possible.


FDA clearance is the first step toward a test being CLIA Waived. Once a test is submitted to the FDA for clearance, they will assign the test a complexity rating. Often times tests will first be approved with a “high” or “medium” complexity rating, and manufacturers can address specific concerns and apply after-the-fact for a preferred complexity rating. In our “space” (instant drug testing), most commonly tests clear the FDA a “waived” complexity rating; mainly as we rarely see any great technological or methodology breakthroughs.


Why does this matter? As you may have noticed, my explanation included the term “medical”, and this is because the threshold for the CMS and FDA applying, would be if the testing is for medical purposes. Addiction medicine is an excellent example of this. As per CLIA regulations (short-form guidance can be found here and here), any facility that performs testing for medical purposes is considered to be a “laboratory”, and would be required to obtain a CLIA Certificate of Waiver, and further would be required to use only tests with a complexity rating of “waived”.


What about a test that has not yet been cleared by the FDA? Test devices and procedures that have not yet been cleared are given the designation of FUO (remember, Forensic Use Only). These tests should only be used by facilities who are testing for reasons that are not medical; criminal justice (drug courts, probation, etc.) is a perfect example of this as the testing is not being used to make diagnostic decisions, but typically only to determine compliance to a program’s requirements.


The good news is that, as it relates to instant drug testing, there is virtually no difference between a waived test and an FUO test, aside from some of the language contained in the instructions/ product insert. As an example, instructions on an FUO test may advise to “read the results in 5-10 minutes”, whereas the CLIA Waived version would say “read at 5 minutes”. Again, removing any room for error that misinterpreting the results might cause.

As always, please reach out to our team for any additional information or guidance.

A Word on External Quality Controls

A Word on External Quality Controls

If you read the instructions that are included in each box of tests (stop laughing, some people have!) then you have seen the recommendation that “positive and negative controls be tested as good laboratory practice to confirm the test procedure and to verify proper test performance”. Every instant test does have built-in procedural controls; “a colored line appearing in the control area confirms specimen volume, adequate wicking, and correct procedural technique”. So, while the built-in controls indicate the test was performed correctly, it does not indicate performance (read accuracy and precision).


So, what are these external controls that the instructions recommend running? In short, they are synthetic urine specimens that are spiked with known and measurable concentrations of target substances, which should consistently provide the same result. For example, an external control to test the Benzodiazepine panel would contain at least 300ng/mL of Oxazepam, which is the calibrator – or target substance – that the BZO panel would react to. Since the instant tests’ accuracy becomes higher the further above cut-off we go, we typically recommend a “+50%” control. With our Benzo example, this means the controls would contain 450ng/mL of Oxazepam.


Since these are simply urine specimens, the controls are run just as you would run any other instant test. You would have one test that you would use the positive controls on – success would be that all the substances that are included positive control would cause a positive result on the corresponding panel on the instant test. You would also run a negative control, with success being none of the panels showing a positive result. We usually provide these controls in 5mL vials, with each vial containing enough specimen to run one test.


Now, of course not everybody pays attention to the instructions, or to the manufacturers’ recommendations. However, depending on the nature of your testing program, this can become more important to heed. This mainly affects healthcare facilities because they fall under the purview of CLIA (Clinical Laboratory Improvement Amendments), which requires that they follow all the manufacturers’ recommendations for using instant tests; they need to run quality controls once per shipment or once per lot, whichever comes first. Some healthcare credentialing bodies go even further than that, requiring that controls also be run once for every thirty days in storage, and once for every new hire.


Overall, it is excellent practice to run the controls per the manufacturers’ recommendations, and it is a quick and easy process, as there is very little difference in the procedure. Also, the cost for the controls is not considered prohibitive for most programs. For more information on this, or if you need to order controls, please reach out to your consultant.

Testing for the Presence of Fentanyl: Surfaces & Residues

Testing for the Presence of Fentanyl: Surfaces & Residues


We are frequently asked about the options for testing a powder or residue found on a participant, or at a facility for the presence of Fentanyl. In other words, if during a routine check of the property (residential, inpatient, correctional facility, etc.), a powder substance or residue is found, the staff may want to test to see if the powder that is found is or contains Fentanyl.

The obvious reason to test is safety, as nobody wants themselves nor their staff to be exposed to Fentanyl without proper safety precautions. Another reason is harm prevention/reduction; some facilities may have reason to test a user’s “stash” to determine if it might be contaminated by Fentanyl. This same could hold true for a better awareness of what substances might be common in their neighborhood.

If you find yourself in one of the above situations (or for any other reason that I may have neglected to include), we have good news: the instant test for Fentanyl, with the aid of a readily available and relatively inexpensive buffer solution, will detect Fentanyl itself. So, in addition to the more common use of testing urine for Fentanyl use, the Fentanyl instant test makes for an excellent and reliable forensic test as well. It makes the most sense to do this with the Fentanyl single-panel, as opposed to multi-panel dip or cup. Although, while it would certainly also work on the multi-panel, it typically makes the most send cost-wise (and ease of use) with the single-panel.

The other good news is regarding the cut-off level/drug concentration: our currently most popular single-panel Fentanyl dip is calibrated to Norfentanyl (the primary metabolite of Fentanyl) at 20 ng/mL (nanograms per milliliter) but will also detect the Fentanyl itself at 200 ng/mL. So, while you might be encountering a very small amount of powder, keep in mind that a nanogram is one billionth of a gram. We can imagine that a microgram (one millionth of a gram) is about the smallest amount of substance we could see with our “bare” eyes. Then two “grains” is already 1,000 times more Fentanyl than what is needed to trigger a positive on the test strip.

Lastly, it is incredibly simple to use, as seen in the instructions below:



If you would like additional information on this or need to order the buffer solution to begin testing in your facility, please reach out to myself or your consultant.


What We Know Now About the Window of Detection for Fentanyl

What We Know Now About the Window of Detection for Fentanyl

Fentanyl use continues to rise, and with increased usage comes increased data, and an increased understanding of the pharmacology of this extremely potent synthetic Opioid. In fact, chronic Fentanyl use is a relatively new phenomenon. I suspect that over time we will get an even clearer picture of what the long-term effects ofFentanyl use and misuse are.

If you had asked me a month ago how long Fentanyl is detectable in urine, I would have given my answer based on the common wisdom at the time: 4-5 days. However, around this time I learned some new information that has forever changed my answer to this question.

The situation was as follows: one of our clients looking at the lab results for one of her participants, asked me for clarification of what the results might mean. The result indication no presence of Fentanyl, but 76 ng/mL of Norfentanyl (the primary metabolite of Fentanyl) was confirmed present. My first thought was use in the preceding 4-5 days – as there was only the metabolite present, which we typically see near the outset of the window of detection. Discussing this further with our client, she indicated that this participant had been in jail for the 2 weeks prior to this specimen. We all know that it isn’t impossible to find drugs in jail, but she was confident this wasn’t the case in this situation. Luckily, while I like to brag about my 20 years’ experience and my boundless knowledge, I do have people I can turn to who have even more experience and an even deeper knowledge than I. My go-to toxicologist told me the story of a family member who had tested positive for Norfentanyl for weeks after last use. She apologized that she could not find any studies to back this up, and this was strictly anecdotal. After digging for a while, I too was unable to find any serious research to back this up. I was frustrated as I was not about to start sounding the alarm based solely on anecdotal evidence. So, I simply set the story aside for the time being.

Fast-forward about 3 weeks when I was discussing lab results with a different client. One of the lab results we looked at was a similarly high level of Norfentanyl confirmed, while Fentanyl was not present – almost an identical looking result to the one that started this. This led to a discussion about Quest Laboratories telling her they were investigating this same theory, and they were compiling Fentanyl confirmation result. More importantly, this led to a renewed (and more frenzied) search for some shred of clinical evidence that there was some truth to this (thanks Jennifer!).

I was finally able to find a reliable source of data in the form of this article from Boston University. It is by no means thorough enough to be the last word on this matter, but it was detailed enough for us to want to share this information with you. In summary, it explains that Fentanyl is lipophilic (which means dissolved in fat cells, as opposed to water), much like THC, and as such will build up over time with chronic use. This means that the window of detection for chronic Fentanyl users can be as long as 26 days or more.



IMPORTANT UPDATE October 2021: It has come to our attention that the original study (linked in the Boston University article) used methodologies that are being called into question. So, while I was careful to include the disclaimer that this is “[not] the last word on this matter”, we feel it is important to note that this information should not be considered actionable and should be considered only theoretical until further studies can be performed, published, and reviewed. It is also our understanding that these further studies are in the works and look forward to providing a more substantiative update in the near future.