Urine drug tests are commonly used to detect illicit drug use. There are two main types of urine drug tests: immunoassays and gas/liquid chromatography-mass spectrometry. Immunoassays use antibodies to screen for drugs and produce a positive or negative result, but can sometimes yield false positives. Gas/liquid chromatography-mass spectrometry is more accurate and can identify specific drugs, but takes longer to run. The most common method of drug testing is the urine drug test due to its low cost, ease of sample collection, and ability to detect drugs for several days after use.

1. By Sham Muhammed (stage 1)

2. What are illicit drugs?
 An illicit drug is defined as any drug which is illegal to
possess or use or any legal drug used in an illegal
manner or miss-used
 Types:
1) Stimulate C.N.S
2) Inhibit C.N.S
3) Hallucinogens
 Highly addictive
 According to national data in 2017 More than
30 million Americans used illicit drugs.

3. A comprehensive list of illegal drugs and unregulated
substances may include:
Ayahuasca Bath salts crack cocaine
ecstasy heroin LSD marijuana
Methampheta-
mine
mushrooms peyote mephedrone
PCP salvia Spice or k2

4. Types of drug tests:
 A drug test (or a urine drug screen UDS) looks for the
presence of one or more illegal or prescription drugs in
a biological specimen.
 There are many types of drug tests including breath test, hair test, saliva/oral
fluid-based drug screen, sweat drug screen, blood test, diagnostic/tox screen
and the most commonly used one which is urine drug test or urine drug screen
(UDS).
 Purposes of drug testing:
 Job employment
 Sports organizations
 Monitoring opioid use
 For recovering people
 Identify for signs of addiction

5. Urine drug test ( UDS)
 Most common testing method:
 Lots of types of drugs can be detected
 High conc. detected
 time-efficient
 Low-cost
 Easy to collect
 Longer detection period
• The detection period of a drug is the period of time a drug
can be detected or found in someone’s biological sample
(in our case: urine)

6.  The detection period depend upon multiple factors: drug class, amount
and frequency of use, metabolic rate, body mass, age, overall health,
and urine pH.
 For ease of use, the detection times of metabolites have been
incorporated into each parent drug for ex; heroin and cocaine
metabolities.
Type of drug Detection time in UDS
heroin Up to 3 days
marijuana Up to 30 days
methadone Up to 4 days
ketamine Up to 11 days
PCP Up to 4 weeks
psilocybin Up to 24 hours

7. There are 2 types of UDS:
1) IMMUNOASSAY ( IA)
 First step of UDS
 Time-efficient
 Cost-effective
 Usually done in test kits ( not in lab.)
 Inaccurate sometimes
 Results are + or -
 Enzyme multiplied
immunoassay technique (EMIT)

8. How do immunoassays ( IA) work?
 Immunoassays rely on the ability of an antibody to recognize and bind a
specific macromolecule
 In some cases, an immunoassay may use an antigen to detect for the presence
of antibodies.
 produce a measurable signal in response to the binding for ex/ either emit
radiation, produce a color change in a solution, fluoresce under light, or can be
induced to emit light.
 the test uses a cutoff point, Any result below the cutoff number (ng/ml) is a
negative screen
 The Department of Health and Human Services (DHHS) has established
specific cutoff levels that define a positive result, These values were developed
to help eliminate false-positive results (eg, poppy seeds causing positive opium
results). This means that the biggest disadvantage of IA’s is that it can be
inaccurate because other substances or drugs can alter the drug test result,

9.  2) GAS/LIQUID CHROMATOGRAPHY – MASS
SPECTROMETRY
 If your immunoassay result comes back +, we then do GC-MS to ensure that
the result wasn’t a false-positive.
 Done in laboratory
 More expensive
 Can take a few days for results.
 More accurate.

10. How does GC-MS OR LC-MS work
 In the GC/MS process, a sample is first injected into a gas
chromatograph, where components are separated according to size
and/or polarity.
 Then, the components pass into a device known as a mass selective
detector. It’s at this stage that a mass spectrum is obtained and
compared against standard reference libraries in order to identify
unknown components in the sample.

11.  an LC-MS system contains an interface that efficiently transfers the
separated components from the LC column into the MS ion source.
The interface is necessary because the LC and MS devices are
fundamentally incompatible.
 These two components, used together, allow a much finer degree of
substance identification than either unit used separately. It is not
possible to make an accurate identification of a particular molecule by
gas chromatography or mass spectrometry alone.
 GC-MS has been regarded as a "gold standard" for forensic substance
identification because it is used to perform a 100% specific test, thus
meaning it has an extremely high sensitivity or specificity for
Identifying molecules

12. References
 (10 January 2022). Drug test. Retrieved January 16, 2022 from:
https://en.wikipedia.org/wiki/Drug_test#:~:text=Urine%20drug%20testing%20is%20an,migr
ates%20upward%20by%20capillary%20action.
 (2021). Enzyme multiplied immunoassay technique. Retrieved January 16,2022 from:
https://en.wikipedia.org/wiki/Enzyme_multiplied_immunoassay_technique
 Beth Sissons. (2018). what to know about urine drug screening. Retrieved January 16, 2022
from: https://www.medicalnewstoday.com/articles/323378
 Debra Stang. (2018). Urine drug test. Retrieved January 16, 2022 from:
https://www.healthline.com/health/urine-drug-screen.
 Georges solutions. (2022). Urine drug test explained. Retrieved January 16, 2022 from:
https://www.youtube.com/watch?v=mLZDIOoryKM.
 Hailey Hudson. (2021). How Long Do Drugs Stay In Your System?. Retrieved January 16, 2022
from: https://www.addictioncenter.com/drugs/how-long-do-drugs-stay-in-your-system/.
 Michael Schatman. (2015). Urine Drug Testing: Immunoassay vs. Laboratory Testing.
Retrieved January 16, 2022 from: https://www.hcplive.com/view/urine-drug-testing-
immunoassay-vs-laboratory-testing.
 (2021). Gas chromatography – mass spectrometry. Retrieved January 16, 2022 from:
https://en.wikipedia.org/wiki/Gas_chromatography%E2%80%93mass_spectrometry.