External quality assessment scheme in Belgium. Heavy metal analyses

Area of Science:

• Environmental Science
• Analytical Chemistry
• Public Health

Background:

• External quality assessment (EQA) schemes are crucial for laboratory performance.
• Heavy metal analysis in biological samples requires accurate and reliable methods.
• Monitoring heavy metal levels in blood is important for public health surveillance.

Purpose of the Study:

• To describe the implementation and functioning of the Quality Control in Belgium (QCB) EQA scheme for heavy metal analysis.
• To improve laboratory performance in heavy metal testing through interlaboratory comparisons.
• To provide national authorities with data on result variability for lead, cadmium, and selenium in blood.

Main Methods:

• The QCB scheme utilizes in-house prepared human blood samples spiked with lead (Pb), cadmium (Cd), and selenium (Se).
• Four annual exercises are conducted, with participants analyzing three control samples.
• Target values are determined using a reference laboratory's results plotted against known added amounts.

Main Results:

• The QCB scheme has been operational since 1993, involving interlaboratory comparisons for Pb, Cd, and Se in blood.
• The scheme provides data on the dispersion of results among participating laboratories.
• Currently, acceptability criteria and measures against poor performance are not yet established.

Conclusions:

• The QCB scheme effectively facilitates interlaboratory comparisons for heavy metal analysis in Belgium.
• The scheme contributes to understanding laboratory performance and result variability.
• Further development is needed to incorporate formal performance criteria and interventions for improvement.