Level of Serum Electrolytes in Clotted Activator Tubes After Centrifugation from Patients at Samrongthap Hospital, Surin Province, Thailand

Abstract

The measurement of electrolyte levels (Na⁺, K⁺, Cl^-, and CO₂) is a critical process supporting patient diagnosis and treatment. In some cases, additional testing is required from the original clotted activator (primary tube) after blood collection for other initial tests. However, delayed analysis may affect result accuracy. This study aimed to investigate electrolyte stability in serum samples from 90 patients. Levels of Na⁺, K⁺, Cl^-, and CO₂ were measured in serum after blood centrifugation at room temperature at 0, 60, 120, 180, and 240 minutes. Results at 60, 120, 180, and 240 minutes were compared to baseline (0 minute) values using a paired t-test with a significance level of 0.05. Findings revealed no significant differences in Cl^- levels at 60 and 120 minutes compared to baseline (p>0.05). Similarly, Na⁺ and K⁺ levels at 60, 120, 180, and 240 minutes showed no significant changes (p>0.05). In contrast, CO₂ levels significantly decreased at all the time points compared to baseline (p<0.05). However, when evaluated against the total allowable error limit (TEa), all electrolyte values (Na⁺, K⁺, Cl^-, and CO₂) at 60, 120, 180, and 240 minutes remained within clinically acceptable ranges. This study suggests that serum samples stored in clotted activator tubes can be analyzed for Na⁺, K⁺, Cl^-, and CO₂ levels up to 240 minutes post-centrifugation without clinically significant deviations. These findings support practical guidelines for extending the allowable processing time for electrolyte testing in routine clinical settings.