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Updated: Oct 6, 2025
Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue
Published on: June 21, 2018
Profiling of Lactate Dehydrogenase Isoenzymes in COVID-19 Disease
Erika Dzsudzsák1, Renáta Sütő2,3, Marianna Pócsi1,3
1Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
Insights
Elevated lactate dehydrogenase (LDH) isoenzymes 3 and 4 activities, not their relative abundance, are linked to worse outcomes in COVID-19 pneumonia patients. This finding aids in predicting disease severity.
Area of Science:
- Biochemistry
- Clinical Chemistry
- Immunology
Background:
- Elevated serum total lactate dehydrogenase (LDH) activity correlates with severe COVID-19 disease severity and outcomes.
- The specific LDH isoenzyme predominantly increased in COVID-19 remains unclear.
Purpose of the Study:
- To investigate the relative abundance and calculated activity of LDH isoenzymes in COVID-19 pneumonia.
- To correlate LDH isoenzyme patterns with disease severity, lung involvement, and clinical outcomes.
Main Methods:
- Analysis of LDH isoenzyme activities using gel electrophoresis in 22 COVID-19 patients.
- Correlation of calculated LDH isoenzyme activities with laboratory parameters, chest CT findings, and clinical outcomes.
Main Results:
- Total LDH activity positively correlated with calculated LDH-3 and LDH-4 activities.
- No exclusive abnormal relative abundance of any LDH isoenzyme was found in COVID-19 patients.
- Higher calculated LDH-3 and LDH-4 activities and an abnormal LDH-4 ratio were associated with unfavorable outcomes and significant lung involvement.
Conclusions:
- COVID-19 pneumonia lacks a characteristic LDH isoenzyme profile.
- Elevated calculated activities of LDH-3 and LDH-4 are indicators of worse clinical outcomes in COVID-19.
Introduction:
Serum total lactate dehydrogenase (LDH) activity was elevated and showed a positive correlation with disease severity and outcome in severe COVID-19 disease. However, it is still unknown whether the relative abundance or calculated activity of any LDH isoenzyme is predominately increased in COVID-19 subjects.
Methods:
Twenty-two consecutive patients suffered from moderate or severe COVID-19 pneumonia were recruited into this study who showed enhanced total LDH activity. The ratio of LDH isoenzyme activities was further investigated using gel electrophoresis (Hydragel®, Sebia) with densitometric evaluation. Calculated activity values of these isoenzymes were correlated with routine laboratory parameters, the degree of lung parenchymal affection based on chest CT and clinical outcome.
Results:
Total LDH activity was raised in the range of 272-2141 U/L and significantly correlated with calculated LDH-3 and LDH-4 activities (r=0.765, P=0.0001; and r=0.783, P=0.0001, respectively). In contrast, the relative abundance of neither LDH isoenzyme was exclusively abnormal in COVID-19 patients. Calculated activity of LDH-3 and LDH-4 demonstrated a modest but statistically significant association with serum ferritin (r=0.437, P=0.042; r=0.505, P=0.016, respectively). When the relationship between the severity of pulmonary affection by SARS-CoV-2 infection and relative abundance of LDH isoenzymes was studied, a larger ratio of mid-zone fractions was observed in the presence of ≥ 50% lung parenchymal involvement. Finally, regardless of LDH isoenzyme pattern, abnormal relative ratio of LDH-4 and higher calculated LDH-3 and LDH-4 activity values were detected in subjects with unfavorable outcome.
Conclusion:
No characteristic profile of LDH isoenzymes can be detected in COVID-19 pneumonia, however, elevated activities of LDH-3 and LDH-4 are associated with worse clinical outcomes.
