Drug Screening

Medicolegal drug testing:

-used in employer drug abuse program to prevent drug-related accidents or crime -used to identify and treat employees with drug abuse problems

Urine window of drug detection.

1-5 days

5 drug categories routinely included in urine screens:

1. amphetamines 2. cocaine metabolites 3. marijuana metabolites 4. opiate metabolites 5. phencyclidine

4 drug classes *not* routinely detected by a urine drug screen:

1. androgenic steroids 2. GHB 3. Anticoagulants 4. Meperidine

4 general drug testing considerations:

1. cross-reactivity 2. specificity 3. cut-off level 4. adulterants

4 urine sample collection considerations:

1. observation 2. color 3. temperature 4. volume

Saliva test window of detection:

10-24 hours (reflects recent use)

What is a blind sample in a urine test?

A negative or spiked sample submitted with the donor's sample.

Drug test that is designed as an initial screen:

EMIT

Easiest test to beat due to lack of specificity:

EMIT

Most widely used drug test due to its low cost:

EMIT

(T/F): Drug tests are usually able to determine when the drug was ingested.

False

(T/F): Hair analysis can determine recent drug use.

False

(T/F): Hair analysis is sensitive to low drug dosage use.

False

(T/F): A negative urine screen means the drug was not present or that the patient did not take it.

False. It means the drug was not detected.

What type of drug test has the longest window of detection?

Hair (usually 90 days based on the collection of 1.5 inches of hair)

Medical drug testing vs. legal drug testing:

Medical drug testing: -Monitor patient's progress -Determine the presence of drugs before treatment -Simple, less expensive method -Unlikely to be used as evidence in court Legal drug testing: -Determine the use of drugs used prior to an accident or crime -Requires a confirmatory test

Primary vs. secondary seals in a urine test:

Primary seal: lid/ cap of a specimen bottle with a tamper proof seal Secondary seal: leak-proof plastic bag in which the specimen bottle is placed

Drug test frequently used in the military:

RIA (radioimmunoassay)

Who determines specific cut-off values in urine drug testing?

Substance Abuse and Mental Health Services Administration (SAMSHA)

(T/F): GC/MS is used as a confirmation test.

True

(T/F): RIA drug tests require a confirmation test.

True

(T/F): A sample from a urine test should be split into two separate specimen bottles.

True. Bottle A: first specimen (30 mL), Bottle B: second specimen (15 mL)

Specimen of choice in drug screenings:

Urine -Collection is non-invasive -Most drugs and metabolites are excreted and are concentrated in the urine -Drugs and metabolites are stable in frozen urine -Usually a clean matrix

Detection times in a urine screen: a. Amphetamine: b. Cocaine metabolites: c. LSD: d. Marijuana metabolite: e. Opioids: f. Methadone: g. PCP:

a. Amphetamine: 2-5 days, possible 2 weeks with heavy use b. Cocaine metabolites: up to 2 weeks, 6 weeks with chronic use c. LSD: 1-2 days d. Marijuana metabolite: 7-10 days, 1 month with chronic use e. Opioids: 2-3 days f. Methadone: 3-14 days g. PCP: 2-10 days

Hair analysis collection requirement (amount needed):

about 60 hairs (thickness of a pencil)

Hospital alcohol testing: What is measured?

alcohol dehydrogenase based assay --> usually measure serum or plasma rather than whole blood

Fatal flaw:

error that raises doubt about the integrity of a specimen or the information concerning the specimen.

Currently the only practical tool for dealing with large sample numbers:

immunoassays

Hair analysis cost compared to urine test:

more expensive

Chain of custody:

procedure used to document the handling of the specimen from the time of donation until it is destroyed.