Biological Monitoring Programmes

Biological Monitoring · Biological Monitoring overview

A defensible biological monitoring programme is a documented cycle: scope, sample, analyse, interpret, communicate, review. Each step has expectations that UK enforcement and civil claims will test if challenged.

Scoping document

The scoping document records why the programme is being run, which substances and biomarkers will be measured, which SEGs are included, the sampling strategy, the laboratory and methods, the reference values used for interpretation, the communication plan and the review trigger criteria.

Sampling strategy

Sample timing is biomarker-specific. End-of-shift sampling is used for most solvent metabolites; pre-shift next-morning for substances with overnight half-lives such as some chlorinated solvents; immediately end-of-shift for short-half-life markers such as urinary mercury (Hg) post-exposure. The strategy is statistically powered to detect a defined excursion above the chosen reference value.

Analysis and quality

Analytical work is performed at a UKAS-accredited laboratory with documented uncertainty of measurement and participation in an external proficiency scheme such as the German GEQUAS or the UK HSL biological monitoring scheme.

Interpretation and reporting

Reports compare each individual to the reference value and present cohort statistics (geometric mean, 90th percentile, range). Trend reporting across campaigns identifies drift in control performance before it reaches the action level.

Review trigger

Predefined trigger criteria — for example, any individual above the BMGV or a cohort GM exceeding 50% of the BMGV — initiate a control review covering LEV, RPE, dermal hygiene, training and work practice.