The influence of blood sample treatment on plasma potassium concentrations in avian blood

Plasma potassium concentrations were determined in racing pigeons (Columba livia domestica), chickens (Gallus domesticas) and man (Homo sapiens) after different storage times of uncentrifuged blood samples at room temperature. In the pigeon plasma potassium concentrations declined rapidly. After 10 min the reduction was 9.5% and declined by 65% after 120 min. No further reduction was noted up to 24 hours. In chickens decreases were also noted but were smaller overall with a 29% decrease being noted after 2 hours. No significant changes of plasma potassium concentrations in human blood were found during the first 2 hours of storage. The need to describe the treatment of blood after sampling is indicated. It is concluded that for most blood chemical measurements plasma is preferred to serum and blood samples should be centrifuged within minutes of sampling.