Impact of prolonged air exposure on stability of carbon dioxide (CO2), chloride (Cl), potassium (K) and sodium (Na)

ADLM 2025 -- Preanalytical handling of patient samples is crucial, as prolonged exposure to air can lead to inaccurate results. In high-volume laboratories with automation, uncapped samples may be exposed to air, causing CO2 loss and altering ion concentrations. Since ions are vital for calculating the anion gap and assessing acid-base imbalances, minimizing preanalytical errors is essential. This study evaluates the effects of exposure time, sample volume and tube size on changes in bicarbonate (dissolved form of CO2), Cl, K and Na concentrations, with creatinine used as a control.