Hyperkalaemia in prolymphocytic leukaemia--a sometimes spurious result. A case report.

A patient suffering from prolymphocytic leukaemia was found to have extremely high serum potassium levels. The mechanism of the apparent biochemical change was investigated and was found to be a spurious abnormality related to in vitro lysis of the large mass of lymphocytes. This in vitro observation has been termed pseudohyperkalaemia and should not be mistaken for genuine disturbances that need treatment.