Analytical Quality Requirements in Human Biomonitoring Programs: Trace Elements in Human Blood

Area of Science:

• Environmental Health
• Analytical Chemistry
• Biomonitoring

Background:

• Human biomonitoring (HBM) programs are crucial for assessing exposure to environmental pollutants.
• Effective HBM study design requires accurate sample size calculations to define exposure trends.
• Key factors influencing sample size include population variability and analytical method performance.

Purpose of the Study:

• To quantify the impact of measurement uncertainty and inter-laboratory variability on HBM sample size requirements.
• To evaluate the contribution of these factors for commonly monitored metals (mercury, cadmium, lead) in blood.
• To inform optimal study design strategies for HBM programs.

Main Methods:

• Sample size calculations were performed using data from one laboratory's measurement uncertainty.
• Inter-laboratory comparison exercise data were utilized.
• Population variability for mercury, cadmium, and lead in blood was incorporated.

Main Results:

• Measurement uncertainty within a single laboratory had minimal influence on required sample size.
• Inter-laboratory variability substantially increased sample size requirements, particularly when population variability was low.
• The use of multiple laboratories significantly elevates sample size needs due to variability.

Conclusions:

• Inter-laboratory variability is a critical factor that must be considered during the planning phase of HBM studies.
• A single-laboratory approach can be a cost-effective strategy to mitigate variability introduced by multiple participating laboratories.
• Optimizing sample size calculations requires careful consideration of both within- and between-laboratory performance characteristics.