MLAB 2401: Clinical Chemistry Keri Brophy-Martinez

1
MLAB 2401 Clinical ChemistryKeri Brophy-Martinez

• Toxicology Overview

2
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

3
Toxin Exposure

• 50 of exposures are intentional (suicide)
• 30 accidental
• 20 Homicide/ Occupational exposure

4
Routes of Exposure and Absorption

• Ingestion
• Inhalation
• Transdermal absorption
• Absorption
• Toxins must enter circulation to cause damage
• Majority of toxins absorbed by passive diffusion

5
Dose-Response Relationship

• Increase in toxic response as the dose is
  increased
• Not all individuals have toxic responses at the
  same level

6
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

7
Analysis of Agents

• Two step process
• Screen/ Qualitative
• Sensitive but not specific
• Confirmatory
• Quantitative
• Specific
• Higher cost

8
Sample Sources

• Urine
• Blood
• Meconium
• Hair
• Nails
• Tears
• Sweat

• Post-mortem
• Vitreous humor
• Gastric fluid
• Solid organ samples

9
References

• 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
  .