356518 tn?1322263642

False negatives...Pitfalls of Urine Drug Monitoring in Pain Care ...

I am always looking for information on the effectiveness and accuracy of the drug test we have to endure. I have just come across this one from Early this year.
It has alot of information on how the UA works and why they are inconclusive most of the time.
I am including the link as I have not posted everything in the article.
The VA study I have posted in my journal and refer members to was done in 2004 I believe. I continue to look for updated material on this as we do get members who have to deal with the mysterious results of a false negatives alot.
I will also post this link in the health pages and journal for future reference.
I have several other studies I am looking at also that addresses false negatives.
With so many having to deal with this problem I try and keep the newest information up here in the community.
When someone has received a false positive it is good to have reference material to do to the doctor with and show that this is an all to common problem.
I do hope it will help someone:)

Drug monitoring in pain practice is often a two-stage process [Leavitt 2005]:

A.Preliminary Screening of patient-provided specimens, usually urine, at the point-of-care (POC) to detect the presence or absence of a limited number of prescribed and non-prescribed drugs of interest. The accuracy and reliability of relatively inexpensive POC screening assays are limited; although, more costly laboratory-performed assays can be of higher quality.

B.Confirmatory Testing techniques, using high-quality methods (eg, GC-MS, LC-MS), are more expensive but highly accurate and reliable. A problem is that these methods sometimes can be too good, detecting small amounts of irrelevant agents or metabolites that are diagnostically unhelpful or confusing.

While it would be presumptuous to caution against the use of urine drug monitoring, there are a number of potential pitfalls worth noting. Here are several common as well as less well-known considerations:

•Detection cutoff-levels do not always take into account passive (innocent) exposure to marijuana or cocaine consumed by others, consumption of poppy seeds (natural opiate), and the use of OTC products that may cross-react with the assay to produce false results [Evans et al. 2009; Reisfield 2009].

•A number of opioids are metabolized by liver (CYP450) enzymes: eg, codeine, hydrocodone, oxycodone, methadone, buprenorphine, tramadol, and fentanyl. Individual patients may have genetic variants of the enzymes, or may be taking inducer or inhibitor drugs, that strongly influence opioid metabolism and, hence, their detectable presence or absence in urine (or blood, or oral fluid if used) [see, Carlozzi et al. 2008; Smith 2009]. For example, the unexpected absence of one of the above opioid analgesics upon testing can be due to rapid metabolism in a patient rather than therapeutic noncompliance or drug diversion.

•Morphine preparations typically contain low levels of codeine as an impurity, which may be detected by high-quality assays in patients who have not been prescribed codeine [Evans et al. 2009].

•Patients prescribed high doses of oxycodone also may test positive for hydrocodone, which is believed to be present as an impurity; analytically this is a true positive, but diagnostically it is a false positive [Evans et al. 2009].

•It has been clinically observed that unanticipated conversions between opioids going beyond common metabolic pathways may occur, and these can be detected by high-quality assays [Haddox 2005]. For example, patients prescribed only codeine might test positive for codeine and morphine, and also hydrocodone and hydromorphone. Patients taking only morphine might also test positive for hydrocodone and/or hydromorphone. While mechanism behind this metabolic phenomenon are not understood, such findings could falsely suggest that patients are taking unauthorized opioids.

•Proprietary, computerized methods have been developed for quantifying the amount of opioid agents in testing samples; these have been based on controlled conditions examining carefully-selected patients [Couto et al. 2009] or pharmacologically adjusted values [Kell 1994, 1995]. Relying on quantitative tests to help determine whether a patient is properly taking the specifically prescribed dose of opioid can be questionable, especially in patients who do not fit typical patterns of metabolism or have other confounding factors. Due to their limitations, quantitative assessments have been eschewed by government agencies where the consequences of misinterpretation could be severe (eg, Drug Courts).

•Even the most high-quality laboratory testing may not deter persons seeking opioids for illicit purposes — they know how to cheat. An entire industry has sprung up offering advice and products to “beat the test” (just insert that phrase into any search engine to see the myriad of solutions being promoted).

•Case reports have noted false-negative results for opioids and cannabinoids in the presence of tolmetin, an NSAID, and for amphetamines due to interference by chlorpromazine (eg, Thorazine®) metabolites. The antifungal agent fluconazole may interfere with the detection of cocaine [Reisfield 2009]. Persons determined to “beat the test” may know about this.

•A popular and effective way to beat the test is by substituting “untainted” urine for one’s own by carrying a concealed specimen into the bathroom. The only way to thwart this is by supervised urine collection (ie, a staff member observing urine leave the patient’s body and fill the cup). While this is required for forensic urine testing, it could be the ruin of a typical medical practice; it is upsetting for patients and demoralizing for staff.

•To avoid the possibility of urine specimen substitution, oral fluid can be collected for use with screening devices employing technology similar to on-site, POC urine screens. Sensitivity and specificity of oral fluid screening and testing are acceptable, but subject to the same limitations of interpretation and confounding factors as urinalysis [Leavitt 2005].

•Urinalysis is unhelpful for detecting alcohol misuse or abuse [Moeller et al. 2008], and alcohol can be more hazardous in combination with opioids than many other drugs.

The above list is certainly not all-inclusive [eg, also see, Carlozzi et al. 2008; Reisfield et al. 2007b]; however, in view of the many caveats, healthcare providers may want to reconsider what they expect to accomplish by drug monitoring as a component of pain care and if it will adequately serve them and their patients
7 Responses
Sort by: Helpful Oldest Newest
82861 tn?1333453911
Great info Sandee.  Can you have this post pinned for future reference?
Helpful - 0
356518 tn?1322263642
Thanks. I will be adding several other articles to this too. I have found alot of information in the references noted too.
This is so very important to the community as we both know how many members have been having this problem.
I wish I could find a percentage rate of patients that have had false positives and are now without treatment. I bet the numbers are staggering.
Helpful - 0
Avatar universal
I am new to this forum so please bear with me and redirect me to previous discussions to clarify my questins as needed.  I wasn't aware that pain management patients without a history of drug abuse issuses were required to sign a contract.  Is that true?
Helpful - 0
356518 tn?1322263642
Yes, most every PMP has patients sign a contract. It really has nothing to do with drug abuse it helps protect the Doctor and patient.
Helpful - 0
82861 tn?1333453911
beano - Yes, many if not most pain clinics include mandatory urinalysis as condition of treatment.  It's really a shame because this practice immediately forces the doctor and patient into a suspicious and adversarial relationship.  They operate from the assumption that every patient either is, or will become, an addict.  Questions about false negative drug screens pop up here on a regular and nearly predictable basis which illustrates just how widespread the problem is.  Many doctors also require that patients submit to either random or scheduled pill counts to verify that the patient is not taking more than prescribed or selling the meds on the street.

I guess I'm one of the lucky ones as my doctor doesn't subscribe to UA and pill counts.  Her goal is to keep patients out of her office as much as possible, so office visits are only required every 3 months or so.  If a patient constantly calls and asks for more meds, that patient will be discharged on the basis that the she obviously cannot help that patient rather than for therapeutic non-compliance.  While it's not always easy to get in to see my doctor due to her limited office presence (her main practice is anesthesiology), I am very happy that when I do go in, it's the doctor herself that I see rather than a PA or nurse practitioner.  In case of emergency she can be easily reached on the phone which saves both of us a trip to the office and another co-pay for me.
Helpful - 0
356518 tn?1322263642
Thank you Jaybay for being more detailed. I was in a hurry but wanted to answer the question so I posted a short answer meaning to come back and further explain:)
I have more studies I will be posting soon:)
Helpful - 0
356518 tn?1322263642
I have included this in the health pages as well as my journal so if you need it for future reference it will be available.
I have also included the medication conversion chart too:)
Helpful - 0
Have an Answer?

You are reading content posted in the Pain Management Community

Top Pain Answerers
Avatar universal
st. louis, MO
317787 tn?1473358451
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
Find out how beta-blocker eye drops show promising results for acute migraine relief.
Could it be something you ate? Lack of sleep? Here are 11 migraine triggers to look out for.
Find out if PRP therapy right for you.
Tips for preventing one of the most common types of knee injury.
Here are 10 ways to stop headaches before they start.
Tips and moves to ease backaches