Plasma lactate dehydrogenase activity will be increased if detergent and platelets are present

Area of Science:

• Clinical Chemistry
• Biochemical Analysis
• Hematology

Background:

• Lactate dehydrogenase (LDH) is a critical enzyme marker in clinical diagnostics.
• Accurate measurement of plasma LDH is essential for disease diagnosis and monitoring.
• Continuous-flow analyzers are widely used in clinical laboratories for high-throughput testing.

Purpose of the Study:

• To investigate the cause of artifactually increased plasma lactate dehydrogenase activity observed during analysis.
• To identify specific factors contributing to inaccurate LDH measurements on the SMAC analyzer.
• To elucidate the role of platelet-derived LDH in plasma measurements.

Main Methods:

• Analysis of plasma lactate dehydrogenase activity using the SMAC (Technicon) continuous-flow analyzer.
• Evaluation of the impact of centrifugation completeness on LDH levels.
• Assessment of the effect of detergent in the dilution buffer on LDH measurements.
• Case study involving a patient with thrombocytosis to demonstrate platelet LDH contribution.

Main Results:

• Plasma LDH activity was artifactually increased when analyzed on the SMAC continuous-flow analyzer.
• Incomplete centrifugation and the presence of detergent in the dilution buffer were identified as causative factors.
• Elevated plasma LDH in a patient with thrombocytosis highlighted the significant contribution of platelet LDH.

Conclusions:

• The SMAC continuous-flow analyzer can produce falsely elevated plasma LDH results.
• Laboratory protocols, including centrifugation and reagent preparation, must be optimized to ensure accurate LDH measurements.
• Platelet activation and lysis can significantly impact plasma LDH levels, particularly in conditions like thrombocytosis.