Main Types of UDT Methods
1. Initial testing drug panels such as:
Use of a One Step Drug Test for Marijuana, Cocaine, Opiates, Amphetamine, Methamphetamine, and Benzodiazepines
Classify substance as present or absent according to cutoff
Many do not identify individual drugs within a class
Subject to cross-reactivity
Either lab based or at Point of Care testing
2. Identify Specific Drugs &/or metabolites with sophisticated lab-based testing; e.g.,GC/MS or LC/MS (GC/MS=gas chromatography/ mass spectrometry & LC/MS=liquid chromatography/ mass spectrometry)
Specifically confirm the presence of a given drug– e.g., morphine is the opiate causing a positive IA(IA=immunoassay)
Identify drugs not included in IA tests (IA=immunoassay)
When results are contested
Detecting Opioids by Urine Drug Testing (UDT)
Most common opiate IA (IA=immunoassay) drug panels
Detect “opiates” morphine & codeine, but doesn’t distinguish
Do not reliably detect semisynthetic opioids
Specific IA (IA=immunoassay) panels can be ordered for some
Does not detect synthetic opioids (e.g., methadone, fentanyl), Only a specifically directed IA
panel will detect synthetics
GC/MS or LC/MS will identify specific opioids
(GC/MS=gas chromatography/ mass spectrometry & LC/MS=liquid chromatography/ mass spectrometry)
Confirm presence of a drug causing a positive IA (IA=immunoassay)
Identify opioids not included in IA drug panels, including semisynthetic & synthetic opioids
Specific Windows of Drug Detection
How long a person excretes drug &/or metabolite(s) at a concentration above a cutoff
Detection time of drugs in urine
Governed by various factors; e.g., dose, route of administration, metabolism, fat solubility, urine volume, & pH
For most drugs it is 1-3 days
Chronic use of lipid-soluble drugs increases detection time; e.g., marijuana, diazepam, ketamine
Interpretation of Urine Drug Testing (UDT) results
Positive Results:
Demonstrates recent use
Most drugs in urine have detection times of 1-3 days
Chronic use of lipid-soluble drugs: test positive for a week or more
Does not diagnose: Addiction, physical dependence or impairment
Does not provide enough information to determine • Exposure time, dose, or frequency of use
Negative Results:
Does not diagnose diversion - More complex than presence or absence of a drug in urine
May be due to maladaptive medication-taking behavior
- Bingeing, running out early
- Other factors: eg, cessation of insurance, financial difficulties
Be aware: Testing technologies & methodologies evolve
Time taken to eliminate drugs – document times of last use & quantity of drugs taken
Differences exist between IA (IA=immunoassay) test menu panels vary
Cross reactivity patterns – maintain list of all patient’s prescribed & Off the counter (OFC) drugs to assist in identifying false-positive results and cut off levels
Opioid metabolism may explain presence of apparently unprescribed drugs