An improved flow injection method for determination of lactate during exercise studies.

Area of Science:

• Clinical Chemistry
• Biomedical Engineering
• Analytical Chemistry

Background:

• Accurate lactate measurement is crucial for assessing metabolic status, particularly during exercise.
• Existing methods for lactate analysis may require larger sample volumes or lack automation.
• Developing efficient and reliable analytical techniques for lactate is essential for clinical diagnostics.

Purpose of the Study:

• To describe an improved enzymatic fluorometric method for automated lactate analysis.
• To validate the method's performance using capillary blood samples.
• To assess the suitability of the method for high-throughput laboratory settings.

Main Methods:

• Development of an enzymatic fluorometric assay for lactate.
• Integration of the assay with a flow injection analysis (FIA) system.
• Analysis of lactate concentrations in perchloric acid extracts of capillary blood.

Main Results:

• The method accurately quantifies lactate in as little as 20 microliters of capillary blood.
• High precision was demonstrated with within-day and between-day coefficients of variation around 2%.
• Lactate stability in extracts was confirmed for at least 15 days at room temperature and 30 days at 4°C, with low blank fluorescence.

Conclusions:

• The improved FIA method provides a sensitive, precise, and stable approach for automated lactate determination.
• This method is suitable for analyzing small capillary blood volumes, making it valuable for exercise physiology and clinical settings.
• The system's ease of use and low operating cost make it highly recommended for laboratories with substantial sample volumes.