Biologic MonitoringA. H. Mehrparvar, MD

Occupational Medicine departmentYazd University of Medical Sciences

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

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

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

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

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

Biomarker of exposure Biomarker of internal dose

Blood lead Urine Mn

Biomarker of effective dose CoHgb

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

Biomarker of effect Measurement of reversible biochemical

changes after an internal dose Not pathological effects Example: inhibition of δ-ALA by lead

Biomarker of susceptibility Possible differences between individuals in

responding to an exposure