Papers And Originals

Falsely High Plasma Potassium Values in Patients with Hyperaldosteronism

Br Med J 1970; 2 doi: (Published 04 April 1970) Cite this as: Br Med J 1970;2:18
  1. J. J. Brown,
  2. R. H. Chinn,
  3. D. L. Davies,
  4. R. Fraser,
  5. A. F. Lever,
  6. R. J. Rae,
  7. J. I. S. Robertson


    The common practice of encouraging forearm exercise as an aid to venepuncture is a potent source of erroneously high plasma potassium levels. This may be sufficient to obscure a suspicion of hyperaldosteronism, with possible serious repercussions in hypertensive patients, in whom the diagnosis of hyperaldosteronism has important therapeutic implications. Plasma is preferable to serum for potassium estimations, and forearm exercise should be avoided before venepuncture for potassium measurements.