The effect of time and temperature variables on routine coagulation tests

Current clinical guidelines recommend specific handling protocols for coagulation samples to ensure accurate test results. Prior research has shown that factors like storage temperature and centrifugation timing can influence test outcomes. However, the exact impact of these variables on prothrombin time and APTT remains unclear. This uncertainty limits standardization across laboratories. No prior work had resolved the stability of coagulation assays under various storage conditions. That uncertainty drove this study to examine how time and temperature affect coagulation test results. The gap motivated researchers to test different sample handling methods. This paper's contribution is to clarify how storage conditions influence test accuracy. By addressing this gap, the study supports better diagnostic reliability. The findings may help refine sample handling protocols in clinical labs.

The study aimed to determine how time and temperature affect coagulation test results. Researchers focused on prothrombin time and APTT, two commonly used assays. The specific problem addressed was the lack of consensus on optimal storage conditions. Motivation came from the need to standardize sample handling. The study tested four distinct sample storage conditions. Each condition represented a different clinical scenario. The goal was to identify which variables most influence test stability. By comparing results across groups and conditions, the study sought to inform best practices.

The study compared four sample storage conditions across four patient groups. Healthy volunteers, non-anticoagulated patients, and patients on oral or unfractionated anticoagulants were included. Blood samples were processed under four distinct protocols. The first group was centrifuged and stored at room temperature. The second group was centrifuged and stored on ice. The third group remained as whole blood at room temperature. The fourth group was stored as whole blood on ice. Coagulation tests were performed at multiple time points up to 24 hours. The study tracked changes in prothrombin time and APTT results. Data collection focused on how storage conditions influenced test outcomes.

Prothrombin time results remained stable for up to 24 hours across all conditions. APTT results were stable for 8 hours but varied in heparin-treated patients. Heparinized samples stored uncentrifuged at room temperature showed a shortened APTT. These samples also demonstrated a 50% decrease in ex-vivo heparin levels after 4 hours. Centrifugation and temperature had minimal impact on prothrombin time stability. APTT stability was more sensitive to sample handling in specific patient groups. The findings suggest that storage conditions matter most for heparin-treated samples. The results highlight the importance of standardized protocols for these patients.

The authors concluded that prothrombin time is stable for 24 hours regardless of storage conditions. APTT stability depends on patient treatment and sample handling. Heparin-treated samples stored uncentrifuged at room temperature show significant changes. These findings suggest that storage protocols should be adapted for specific patient groups. The study does not propose new diagnostic tools or future research directions. The authors emphasize the need for careful handling of heparinized samples. They suggest that centrifugation and temperature control are critical for APTT accuracy. The results support the development of more precise handling guidelines.