Module 5: Urine Drug Test Flashcards
rationale for including UDS in OAT
- more sensitive than blood (blood is cleared quicker than urine)
- establish accountability and monitor progress
- guide decisions about OAT dose
- reveal unintended drug exposures
- motivate clients: positive feedback if UDS-ve, and desire to stay clean
Note: some clients express embarrasement/degradation about use
limitations of UDS
- embarrassing / denigrating to some clients (paternalistic)
- hassle to do UDS in addition to picking up carries
- +UDS cannot diagnose SUD, or dose/frequency used
UDT Guidelines: oral OAT vs injectable OAT?
UDS only for oral OAT
iOAT has low risk of diversion, and already frequent monitoring by HCP
UDT Guidelines: frequency of monitoring
Initial assessment before initiation
qweekly during stabilization phase
q1-3mos after stabilization (randomly or scheduled, adjusted based on risk and goals)
UDT Guidelines: timing of monitoring (and rationale)
sample provided prior to receiving OAT
preferably early morning
rationale: fewer false positives, increases adherence
UDS: Drugs of Abuse vs Broad-spectrum toxicology screen
Drugs of Abuse screen (typically immunoassays): opioids, stimulants, benzos, THC
Broad-spectrum tox screen (chromatography): comprehensive, specific drug testing
UDS enzyme Immunoassays: how they work
- antibodies present to bind to drug/metabolite
- also present are drug/metabolites labelled with an enzyme
- external drug/metabolite competes with labelled drug/metabolite
- the more external drug/metabolite present, the more free enzyme activity is seen
UDS Enzyme immunuassays: pros vs cons
pros:
- quick
- POCT available
- can match class as well as specific compounds
cons:
- high cross-reactivity (so less specific)
- susceptible to tampering
UDS chromatography pros vs cons
pros:
- very specific (individual drugs not just class detection)
- monitor adherence: detects methadone and metabolite, or both bup and nlx
- detects other prescribed meds too
- resistant to tampering (b/c specific) and can detect tampering
cons:
- expensive (chromatography + mass spect usually)
- must request specific drug/metabolite
- no POCT
Hair analysis for substance use
- not recommended as routine test
- costly, highly specialised
- can show long-term pattern of use
- depends on hair colour, type and hair dyes / perms
UDS pre-/post-test procedures
- clients leave heavy bags and clothing outside
- clients wash hands (to avoid contamination)
- provide 50-60ml (more than is needed) to reduce tampering
- collection area: no running water, soap or cleaning. Add bluing agents to water
- check temperature of sample (to assess authenticity)
Responding to suspected tampering
- recheck as soon as possible (give water)
- check temp (low when dilution)
- check pH (altered if masking with other substances)
- check Creatinine levels (low with dilution / water-loading)
- send for chromatography to verify (methadone vs methadone metabolites)
- establish pattern (eg. over three weeks)
- confront patient empathetically – not punitively; explore concerns, ways of improving
Screening for Alcohol use: rationale
- acute alcohol use increases effect of methadone (sedation)
- chronic alcohol use decreases methadone effect
- alcohol/benzodiazepine use increases methdadone-related death
Testing for alcohol use: options
- UDS (ethylglucuronide): 1-3 days after use (sensitive to many etoh sources)
- breathalyzer
Reasons for positive alcohol on UDS
- recent use (regular, large amounts)
- impaired liver function or alcohol metabolism
