Harmonisation of seven common enzyme results through EQA.

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Biotechnology

Background:

• Harmonisation of laboratory results is crucial for optimal patient care.
• External Quality Assessment (EQA) programs can drive national harmonisation efforts.
• Commutable samples are essential for accurate inter-laboratory comparisons.

Purpose of the Study:

• To assess the success of a national harmonisation initiative for seven enzymes.
• To evaluate the implementation of International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) traceable results.
• To confirm the stability and commutability of EQA samples used in the harmonisation process.

Main Methods:

• Preparation of EQA samples using human serum spiked with human recombinant enzymes.
• Assignment of target values using IFCC Reference Measurement Procedures.
• Inclusion of identical samples in EQA programs across multiple occasions (2012-2013) to assess stability and commutability.
• Encouraging laboratories to report IFCC traceable results.

Main Results:

• 95% of 223 participating laboratories reported IFCC traceable results, with high success rates for most enzymes.
• Excellent recovery of assigned target values (mean 99%) and low inter-laboratory coefficients of variation (CV) (mean 4%) were achieved.
• Commutability of the EQA samples was confirmed, and sample stability was demonstrated across different EQA program years.

Conclusions:

• The EQA-initiated national harmonisation of seven enzymes was highly successful.
• High implementation of IFCC traceable results (95%) and excellent analytical performance (99% recovery, 4% CV) were achieved.
• The use of stable, commutable samples and IFCC reference procedures facilitated successful harmonisation.