Coloring the toilet water blue prior to sample collection and assessing the urine temperature within 4 minutes of collection (should be between 90☏ and 100☏) are additional measures to check for sample tampering. Such aberrant behavior should be considered in the context of the entire patient presentation with a provider using his or her clinical judgment to assess this possibility. Intentional dilution may occur either with intentional ingestion of copious amounts of water or by adding water to the urine sample from the restroom sink or toilet. Patients who drink a lot of water, consume caffeine, take diuretic medications, have disorders of antidiuretic hormone, or other physiologic disturbances affecting urinary concentration may produce less concentrated urine. Urine samples with such a low creatinine level are less concentrated, and urine drug concentrations may fall below the reporting threshold in such samples. If evaluating urine results, is the sample dilute? Is the urine pH elevated?Īegis provides special report comments to alert providers when the urine creatinine falls below 20 mg/dL. Consider recent gastrointestinal illness in the interpretation of unexpected negative results. Vomiting and diarrhea can disrupt normal absorption and metabolism of medications and reduce excreted amounts to undetectable levels. Has the patient recently experienced vomiting or diarrhea? In a study by Cody, et al., where subjects ingested Adderall 20 mg daily for five days, urine drug concentrations declined following drug discontinuation to below the Aegis threshold of 250 ng/mL after 27 to 45 hours, depending on the patient.
If a patient provides a urine sample on a Monday, for example, and they have been without their amphetamine since the previous Friday, a negative result may be consistent with this dosing. This type of dosing schedule is typically discussed between provider and patient so the provider is aware of how often the patient may need a new prescription. Many patients taking amphetamines for attention or hyperactivity disorders take a break from their medication on weekends, holidays, or other times when their symptoms are not as disruptive (time away from school or work). When was the patient’s last dose? Was the sample collected after a “drug holiday”? Providers wishing to assess compliance of methylphenidate medications (i.e., Daytrana®, Ritalin®, Quillivant XR®, Metadate ER®, Aptensio XR®, Cotempla XR-ODT®, QuilliChew ER®, Concerta®, Methylin®, Ritalin LA®, Focalin®, Focalin XR®) may consider adding this test which is available in both urine and oral fluid.Įxample of unexpected negative amphetamine result in patient actually prescribed methylphenidate (Methylphenidate testing was added for the sample after consultation with Aegis Clinical Team): Methylphenidate is structurally distinct from amphetamine, and undergoes a separate testing process at Aegis. However, a common misconception is that methylphenidate products are also included in this testing. The pharmaceutical amphetamine products mentioned above are detected as amphetamines on Aegis testing. What medication is the patient prescribed? In the case of unexpected negative amphetamine results, there are several points to consider:Įxample of Unexpected Negative Amphetamine Result: 1Įxample of Expected Positive Amphetamine Result:Įxample of Unexpected Positive Amphetamine Result: Amphetamine is also a metabolite of methamphetamine, but in the case of methamphetamine exposure, methamphetamine is typically also present.Pharmaceutical amphetamine products such as Adderall®, Adderall XR®, Vyvanse®, Dexedrine®, Evekeo®, Adzenys XR®, Dynavel XR®, Mydayis® or the generic equivalents of these products.In the case of unexpected positive amphetamine results, consider the following drug exposures: Results of drug testing may be unexpectedly negative or positive. The information provided here is intended to assist providers with deciphering amphetamine results from Aegis, which have undergone definitive testing by liquid chromatography / tandem mass spectrometry prior to reporting. definitive testing methods, and may differ among laboratories. Please note that the interpretation of amphetamine assays differs when using presumptive vs. When reviewing unexpected drug testing results, many providers question, “What did my patient actually take?” In this month’s clinical update, we examine the interpretation of amphetamine results from Aegis Sciences Corporation. What Did My Patient Actually Take? An Overview of Amphetamine Results Tuesday, June 11, 2019