Biological Monitoring Interpretation

Exposure Indices · Exposure Indices overview

Interpreting biological monitoring data correctly requires understanding the biomarker's specificity, the cohort distribution, the relevant reference value and the realistic confounders before any conclusion is drawn about control adequacy.

Individual vs group interpretation

A single individual result is informative only against a written intra-individual reference range. Cohort statistics — geometric mean, 90th percentile, range — describe whether the control regime is working at the population level, which is the question regulators and duty-holders need to answer.

Creatinine correction

Urinary biomarkers must be corrected for urine concentration. Creatinine correction is standard; specific gravity correction is used where renal function is impaired or where the biomarker guidance specifies it. Samples outside the acceptable creatinine range (typically 0.3–3 g/l) are re-sampled.

Confounders

Diet (benzoates raise hippuric acid; fish raises total arsenic), smoking (raises urinary cadmium and S-PMA), and lifestyle exposures all confound non-specific biomarkers. A documented exposure history accompanies every sample.

Reference value selection

HSE BMGV where one exists; ACGIH BEI otherwise; published German BAT or French VLB as supporting values. Each interpretation must cite the value used and the matrix and timing required.