Correlation of spurious potassium elevation and platelet count in dogs

Paired serum and plasma electrolyte determinations were measured on 26 dogs. The difference between plasma and serum electrolyte concentrations was compared to the platelet and leukocyte counts. An increase in serum potassium concentration over plasma potassium concentration was found which correlated linearly with the platelet count. No correlation with white cell count was found. A statistically significant increase in serum sodium concentration over plasma sodium concentration was also noted, however, this change did not correlate with the number of platelets or white cells. It is concluded that thrombocytosis, previously known to cause spurious elevation in serum potassium concentration in humans, can also do so in dogs and, presumably, other species.