Pseudohyperkalemia in Akitas.

Hyperkalemia was observed in a clinically normal Akita with normal ACTH stimulation test results, endogenous ACTH concentration, and SUN concentration. A diagnosis of pseudohyperkalemia caused by red cell hemolysis was made by comparing plasma potassium content from hemolyzed and non-hemolyzed specimens. Red cell potassium content was measured in 8 Akitas and 6 non-Akita control dogs. Six of 8 Akitas had high erythrocyte potassium content relative to their plasma and to that of the control dogs. Five of eight Akitas had microcytosis. Plasma from affected dogs had high potassium content after being refrigerated in contact with red cells for 4 hours or more. The increase in plasma potassium content was progressive with prolonged contact with the red cells and was accompanied by a decrease in plasma sodium content.