PAIN MEDICATION

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MYTHS AND FACTS

There are always the questions of “What can the lab tell me?” or “What does this test result mean?”

Urine test results can be interpreted for adherence only. Compliance includes the component of whether the patient is taking the dosage prescribed.

From “Urine Drug Testing in Clinical Practice. Dispelling the myths and designing strategies”, California Academy of Family Physicians and Pharma Com Group, Edition 3, 2006.

“At this time, there is no scientifically validated relationship between the amount of drug taken and urine drug concentration. Therefore, a UDT (urine drug test) cannot indicate the amount of drug taken, when the last dose was administered, or the source of that drug. Recently, some laboratories have offered technology to compare a patient’s UDT result to an expected range for a drug – they claim that comparing a normalized test result concentration to the expected range can measure compliance with the prescribed dose (reporting: in range, low, or high). Although their protocol may calculate a normalized value based on the patient’s height and weight, the specimen’s pH and specific gravity, and prescription dosage, many other factors can influence the absorption, distribution, metabolism, and elimination of a drug. These include genetic polymorphisms (eg. enzyme deficiencies), renal and hepatic function, disease states, body surface area and muscle mass, cardiac output, drug-drug interactions, drug-food interactions, and age. Therefore, at this time, UDT measurements should not be used to extrapolate backward and make specific determinations regarding dose and compliance with the prescribed drug. Software and laboratory products have not yet been fully validated scientifically and peer reviewed in the medical literature. Interpreting a UDT beyond the current scientific knowledge may put healthcare professionals and patients at medical and/or legal risk.”

Urine drug tests, as the name is normally used, indicates regulated testing for employment, for cause, probation, etc. This type of urine drug test is not appropriate for treatment monitoring (medical purposes). They test for a very limited number of compounds and administrative cutoffs that are set too high for medical purposes. Medical urine drug testing should be performed to reflect the laboratories analytical capabilities (Limit of Detection) and contain at a minimum the most common compounds used in treatment.