Stability of whole blood samples at different temperatures: a systematic review

Blood samples collected outside the hospitals are primarily transported as whole blood. During this transportation, blood sample integrity is highly dependent on conditions such as ambient temperature and mode of transportation, and these conditions are not always sufficiently controlled. Thus, samples may be exposed to time and temperature combinations outside the typically studied and recommended conditions. For laboratories to make recommendations regarding transportation and handle samples that exceed these recommendations correctly, an overview of analyte stability outside the recommended storage conditions is warranted. The objective of this systematic review was to investigate and summarize studies on the effects of temperature and storage time on stability of analytes commonly requested by general practitioners in Denmark. A systematic search of Embase and PubMed was performed on in July 2024 identifying 4,006 potential sources. 60 original studies were included in the review. Twenty-eight out of 32 investigated analytes were stable at 20-23 °C for up to 8 h and many analytes were stable for 8 h at temperatures above and/or below 20-23 °C. Results for stability of lactate dehydrogenase and potassium were conflicting. No data were found for methylmalonic acid, total thyroxine, and total triiodothyronine. In conclusion, this systematic review provides comprehensive data for clinical laboratories to use when evaluating criteria for transportation of whole blood samples. Most analytes were stable after prolonged transportation even after failure to maintain room temperature during transportation; however, attention should be paid to lactate dehydrogenase and potassium, where data were conflicting even under typically recommended conditions.