Comparability of the LDH measurement and analysis based on external quality assessment

Lactate dehydrogenase (LDH) is a critical enzyme widely used in clinical diagnostics. However, variations in measurement systems can lead to inconsistent results, potentially impacting clinical decision-making. This study aimed to evaluate the comparability of lactate dehydrogenase measurements by comparing routine methods with the IFCC reference method, and to analyze the standardization status of LDH testing through external quality assessment (EQA).

We analyzed 40 individual serum samples using four routine LD measurement systems: Siemens ADVIA 2400, Hitachi 7600/BioSino, Beckman AU5800, and Roche Cobas C501, alongside the IFCC reference method. The analytical quality specification (±6.4 %) was based on biological variation. Our study also included a comprehensive external quality assessment (EQA) program conducted by the Beijing Center for Clinical Laboratory (BCCL) over three years (2020, 2021, and 2023) to evaluate the consistency and reliability of LD measurements across different reagents. The acceptance limit is based on the requirement of desirable biological variability (±11.4 %).

All four measurement systems showed strong correlations with the IFCC reference method (r ≥ 0.98). Relative average deviations ranged from -5.23 % to 3.71 %, within the acceptable biological variation limit. External quality assessment revealed high pass rates (94.9 %-98.7 %) across reagent groups, with significant improvements observed in some reagent groups from 2020 to 2023..

While the four LD measurement systems demonstrated good correlation with the IFCC reference method, some systems require further standardization. The study provides valuable insights into LD measurement accuracy and supports ongoing efforts to enhance laboratory testing comparability.