Stability of plasma and erythrocyte fatty acid composition during cold storage.

BACKGROUND: The purpose of the present experiment was to determine if the fatty acid composition of plasma and erythrocyte lipids remains stable when stored at -80 degrees C. This was accomplished by repeating the fatty acid analysis of plasma and erythrocyte samples that had been analysed originally as part of two separate experiments. METHODS: The original plasma and erythrocyte fatty acid analysis was completed on average within 9 and 18 months, respectively, of collecting the blood samples; the repeat analysis was done on average 2.5 and 2 years, respectively, after the initial work. All samples were stored at -80 degrees C. Identical procedures for gas-liquid chromatographic analysis of fatty acids were used for the original and repeat analysis. Plasma triglyceride and erythrocyte phosphatidylcholine fatty acids were measured. RESULTS: The fatty acid compositions of plasma triglyceride and erythrocyte phosphatidylcholine were virtually unchanged between the original and repeat analysis. CONCLUSIONS: In combination with the results of other studies that have found fatty acids to be stable for 1 year at -60 degrees C, the present results demonstrate that the fatty acid composition of plasma and erythrocyte lipids is stable for nearly 4 years when stored at -80 degrees C.