In vitro analytical interference of L-ascorbic acid in enzymatic assays based on the Trinder reaction

Introduction: Ascorbic acid, a water-soluble compound with antioxidant properties, can interfere with several enzymatic methods used in clinical biochemistry. It can consume hydrogen peroxide, thereby affecting the Trinder reaction, a crucial step in the assessment of glucose, total cholesterol, and triglycerides. This study aims to evaluate the impact of this interference in two different biological matrices. Materials and Methods: This is an in vitro experimental study with an analytical purpose, conducted in the Biochemistry Department of the University Hospital Center of Oran, Algeria. The study evaluates the interference of L-ascorbic acid on the measurement of three commonly prescribed biochemical parameters: total cholesterol, glucose, and triglycerides. Two biological matrices were used: a commercial control serum and a pool of human serum. For each analyte, increasing concentrations of L-ascorbic acid were prepared and added to each of the studied biological matrices, then analyzed. Results: Results showed negative and significant interference of ascorbic acid with glucose and total cholesterol assays. A marked decrease in measured concentrations was observed starting from a molar ratio of 0.065:1 for glucose and 0.0325:1 for total cholesterol, reaching up to 100% interference at higher concentrations in both biological matrices. In contrast, ascorbic acid showed minimal interference with the triglycerides assay, even at high concentrations. Conclusion: Ascorbic acid significantly interferes with the measurement of glucose and total cholesterol, highlighting the importance of considering this interference in clinical biochemistry, especially in patients receiving ascorbic acid supplementation.