Ten electrophoretic methods compared with a selected method for quantifying lactate dehydrogenase isoenzymes in serum

Area of Science:

• Clinical Chemistry
• Biochemical Assays
• Enzyme Kinetics

Background:

• Lactate dehydrogenase (LD) isoenzymes are crucial biomarkers in clinical diagnostics.
• Accurate determination of LD isoenzyme activity is essential for disease diagnosis and monitoring.
• Standardization of commercial LD isoenzyme assays remains a challenge.

Purpose of the Study:

• To evaluate and compare the performance of 10 commercially available lactate dehydrogenase (LD) isoenzyme determination methods.
• To assess the accuracy and precision of these commercial methods against a reference standard.
• To identify the most reliable commercial assays for clinical laboratory use.

Main Methods:

• Utilized the McKenzie and Henderson Selected Method as the reference standard for comparison.
• Compared 10 distinct commercial kits for lactate dehydrogenase (LD) isoenzyme analysis.
• Expressed results as a percentage of total LD activity, analyzed using two densitometers with <1.4% average difference.

Main Results:

• All tested methods showed generally comparable results via Bland-Altman plots and correlation analyses.
• Commercial methods tended to underestimate LD-1, LD-2, and LD-3, while overestimating LD-4 and LD-5 compared to the reference.
• Coefficient of Variation (CV) exceeded 20% for LD-4 and LD-5 in several assays, indicating lower precision for these isoenzymes.

Conclusions:

• Significant discrepancies exist in LD isoenzyme quantification among commercial assays.
• Helena Iso Dot and LD-VIS assays demonstrated the best overall accuracy, followed by Corning LD Flur.
• Gelman LDH Isozyme, Sebia Hydragel, and Beckman Paragon assays exhibited the poorest accuracy, necessitating caution in their clinical application.