Trace elements in body fluids: external quality assessment scheme in The Netherlands

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Laboratory Medicine

Background:

• External quality assessment schemes (EQAS) are crucial for monitoring laboratory performance.
• Trace element analysis in body fluids is vital for diagnosing and managing various health conditions.
• The SKZL in The Netherlands organizes EQAS for trace elements in biological samples.

Purpose of the Study:

• To evaluate the performance of medical laboratories participating in trace element EQAS.
• To assess accuracy, precision, and linearity of trace element measurements.
• To identify areas for improvement in interlaboratory consistency and reference range comparability.

Main Methods:

• Voluntary participation of medical laboratories in the EQAS.
• Use of laboratory-prepared frozen samples (whole blood, serum, urine) fortified with 12 trace elements (Tl, Cd, Co, Hg, Se, Pb, Mg, Li, Al, Cu, Zn, As).
• Evaluation of key performance indicators including mean recovery, intra-laboratory variation, and linearity.

Main Results:

• Acceptable mean recovery rates were observed across participating laboratories.
• Intra-laboratory variation and linearity of measurements were generally satisfactory.
• Significant challenges remain in reducing interlaboratory variation and harmonizing reference ranges and interpretation criteria.

Conclusions:

• Current EQAS for trace elements in body fluids demonstrate good intra-laboratory performance.
• Interlaboratory comparability and standardization of reference ranges require substantial improvement.
• Further efforts are needed to enhance the overall reliability and consistency of trace element analysis in clinical laboratories.