Investigating Differences in Bicarbonate Levels: Exploring Discrepancies between Venous and Arterial Measurements and Evaluating Stability through Time-point Assessments

Abstract

Introduction: Evaluation of acid-base status is crucial in critical care settings, with bicarbonate serving as a key indicator of electrolyte distribution and anion deficit. This study explored the challenges and uncertainties surrounding the quantification and stability of bicarbonate levels, crucial for accurate clinical assessments. Methods: The study conducted in the clinical biochemistry laboratory of a tertiary care hospital involves a comparative analysis between serum and arterial bicarbonate levels. We examined serum bicarbonate in 31 patient samples, with concurrently calculated arterial values obtained from blood gas analysis reports of the same patients. Additionally, the stability of serum bicarbonate was assessed at different time intervals. Results: A significant correlation was observed between serum and arterial bicarbonate (r = 0.91), which was reinforced by Bland-Altman analysis. However, the stability assessment revealed a decrease in serum bicarbonate levels at 2 and 4 hours. Conclusion:This study contributes to the exploration of simplified methods for assessing acid-base status, particularly valuable in less-equipped conditions. The findings underscore the necessity for awareness among healthcare professionals regarding the impact of preanalytical variables, particularly uncapped tube storage, on serum bicarbonate levels.