Changes in potassium and sodium concentrations in stored blood

Potassium is the principal intracellular cation with sodium being the principal extracellular cation. Maintenance of the distribution of potassium and sodium between the intracellular and the extracellular compartments relies on several homeostatic mechanisms. This study analysed the effect of blood storage on the concentrations of potassium and sodium in stored blood and also determine any variations that may exist in their concentrations. 50mls of blood was sampled each from 28 units of evenly mixed donated blood in citrate phosphate dextrose adenine (CPDA-1) bags immediately after donation into satellite bag and stored at 4oC. Potassium and sodium concentration determinations were done on each of the 28 samples on day 0 (before blood was initially stored in the fridge), day 5, day 10, day 15 and day 20 of storage using the Roche 9180 ISE Electrolyte Analyser (Hoffmann-La Roche Ltd, Switzerland). data analysis showed significant changes in the potassium and sodium concentrations with a continuous rise in potassium and a continuous fall in sodium. A daily change of 0.59mmol/l and 0.50mmol/l was observed in the potassium and sodium concentrations respectively. We showed steady but increased daily concentrations of potassium and decrease concentrations of sodium in blood stored over time at 4oC.