1. Biologic Monitoring A. H. Mehrparvar, MD Occupational Medicine department Yazd University of Medical Sciences

2. Introduction  Environmental monitoring vs biologic monitoring  Prediction of biologic levels by environmental monitoring  Sources of variability: Different sources of exposure RR Rate of metabolism and excretion Adipose tissue level PPD

3. Introduction  Assesses the extent of exposure  Indirectly assesses health effects  Probability of illness, never diagnostic  Abnormal biologic monitoring levels: Multiple measurements  Timing of collection very important: DS, EOS, EWW, PNS

4. Biologic monitoring program  Necessary conditions: Determinant Method of analysis Sample collection Interpretation of results Responding action  Sufficient conditions: Environmental monitoring  Conducted  Not adequate  Not feasible Substances Exposure routes

5. Biomarkers  Biologic marker or biomarker: any substance, structure or process that can be measured in the human body or human body products, and may influence or predict disease Biologic monitoring: Measuring a chemical, its metabolite or its non-adverse effect in a tissue sample in order to monitor exposure

6. Biomarkers (cont.)  Classification:  Biomarker of exposure  Biomarker of effect  Biomarker of suceptibility

7. Biomarker of exposure  Biomarker of internal dose Blood lead Urine Mn  Biomarker of effective dose CoHgb

8. Biomarker of exposure (cont.)  Characteristics:  Correlation with exposure  Correlation with target tissue dose  Reversibility  Appropriate sampling method

9. Biomarker of effect  Measurement of reversible biochemical changes after an internal dose  Not pathological effects  Example: inhibition of δ-ALA by lead

10. Biomarker of susceptibility  Possible differences between individuals in responding to an exposure