Substance Abuse (chem Path) Flashcards
What are conditions that need drug testing? (9)
-Emergency care
-Psychiatric consultation
-Sports
-Forensic
-Accident investigation
-Addiction treatment programs or rehabilitation centers.
-Pain management clinics
-Patient awaiting organ transplant
-Risk management
What are the four important considerations in drug testing? (4)
-Ingestion route
-Detection window
-passive/environment exposure
-cross-reacting substances
What are the three main routes of ingestion of drugs?
-Oral, inhalation/smoking, injection.
What are the characteristics of injection and smoking routes of ingestion? (5)
-The parent drug bypasses the GIT absorption and 1st pass liver metabolism, hence it has high concentration.
-The drug is immediately taken by the blood.
-There is a rapid uptake of the drug by the tissues which causes it to have a short half life.
-Short detection window.
-Samples we can use to test are blood and oral fluid.
What are the characteristics of the oral ingestion route?
-Slower GIT absorption
-Undergoes first pass metabolism
-Longer half life and detection window.
-High concentrations of both parent drug and metabolites.
What is a detection window?
An amount of time an illicit drug produces positive results in a test after it was last used.
Factors that the detection window depends upon (6)
-Time of last use
-Dose taken
-Urine concentrations
-Metabolites
-Half life
-Kidney and liver function
What are the testing methods for drugs?
-Immunoassay test (screening)
-Gas/liquid chromatography (confirming)
What are immunoassay tests?
Are biochemical tests that measure the presence or concentration of a molecule in a solution using an antibody or antigen.
The most common type of an immunoassay test?
Point of care testing (POCT)
What does a negative POCT mean? (6)
-Patient hasn’t taken illicit drugs.
-Drug that was tested for was not taken.
-Low dose was taken.
-Patient does not take the drug regularly.
-Drug was smoked and not ingested.
-Detection window has passed.
What are the samples used for drug testing?
-Blood, urine, oral fluid, sweat, hair and nails, breath and meconium (baby’s first poop).
What are the substances detected in urine tests? (4)
Amphetamines
Benzodiazepines
Opioids
Cannabis
What are interferences?
These are substances that interfere with the results of the test by altering the concentration of the analyte in solution or alter antibody binding.
What are some of the examples of interferences in amphetamine assays?
-Vick’s vapour inhaler
-Promethazine
-Chlorpromazine
-Metformin
-Ephedrine
-Pseudoephedrine
