Effects of storage on venous and capillary blood samples: the influence of deferoxamine and butylated hydroxytoluene on the fatty acid alterations in red blood cell phospholipids.

Fatty acid concentrations in plasma and red blood cell phospholipids isolated from paired venous and capillary blood samples were compared and the effect of storage at -20 degrees C was evaluated as well. Plasma fatty acid profiles from venous and capillary blood were found to be comparable and not affected by up to four weeks of storage, while fatty acid profiles of venous and capillary red blood cells were no longer comparable after four weeks. Substantial losses of long-chain polyunsaturated fatty acids were observed in capillary red blood cells. To investigate whether the observed long-chain polyunsaturated fatty acids loss could be prevented, capillary red blood samples were stored for up to one year at -50 degrees C in the presence of the iron-binding agent deferoxamine or the free radical scavenger butylated hydroxytoluene. Both compounds protected the long-chain polyunsaturated fatty acids. Similarly, storage of red blood cell lipid extracts at -50 degrees C for up to one year was not associated with reduced levels of long-chain polyunsaturated fatty acids. In conclusion, the lipid loss from capillary red blood cells can be reduced for at least one year during storage at -50 degrees C with prior addition of either a metal chelating compound or a free radical scavenger, or by preparing lipid extracts of the samples within one week of blood collection.