Transcript Overview of Toxicology

MLAB 2401: CLINICAL
CHEMISTRY
KERI BROPHY-MARTINEZ
Toxicology: Overview
TOXICOLOGY

Study of adverse effects of xenobiotics in humans


Xenobiotics- chemicals/drugs not normally found or
produced in the body.
Comprised of four disciplines
Mechanistic: cellular and biochemical effects of toxins
 Descriptive: Utilization of animal results to predict
human effects
 Forensic: Medicolegal consequences of toxin exposure
 Clinical: correlation between toxin exposure and
disease

TOXIN EXPOSURE
50% of exposures are intentional (suicide)
 30% accidental
 20% Homicide/ Occupational exposure

ROUTES OF EXPOSURE AND ABSORPTION
Ingestion
 Inhalation
 Transdermal absorption


Absorption
Toxins must enter circulation to cause damage
 Majority of toxins absorbed by passive diffusion

DOSE-RESPONSE RELATIONSHIP
Increase in toxic
response as the dose is
increased
 Not all individuals
have toxic responses
at the same level

TERMS

Acute toxicity
Single short term exposure to a substance
 Immediate toxic effects are seen


Chronic toxicity
Frequent re-exposure for extended periods
 Doses do not cause immediate response

ANALYSIS OF AGENTS

Two step process

Screen/ Qualitative


Sensitive but not specific
Confirmatory
Quantitative
 Specific
 Higher cost

SAMPLE SOURCES
Urine
 Blood
 Meconium
 Hair
 Nails
 Tears
 Sweat


Post-mortem
Vitreous humor
 Gastric fluid
 Solid organ samples

REFERENCES


9
Bishop, M., Fody, E., & Schoeff, l. (2010). Clinical
Chemistry: Techniques, principles, Correlations. Baltimore:
Wolters Kluwer Lippincott Williams & Wilkins.
Sunheimer, R., & Graves, L. (2010). Clinical Laboratory
Chemistry. Upper Saddle River: Pearson .