Investigation of outpatients referred to a chemical pathologist with potential pseudohyperkalaemia

Abstract

Before a problem can be treated, it must be confirmed and its aetiology identified. A systematic approach to investigate potential pseudohyperkalaemia has been presented. This confirmed the clinician's suspicion of pseudohyperkalaemia and in the majority of patients the aetiology was also identified. The use of serum and plasma potassium with an FBC in the initial investigation will identify whether clotting or a haematological abnormality is the cause in about half of the cases. Assay of whole-blood potassium is less important as centrifugation is a rare cause. Time to centrifugation is likely to play a major part in the majority of the remaining cases.