title: The phenomenon of seasonal pseudohypokalemia: effects of ambient temperature, plasma glucose and role for sodium-potassium-exchanging-ATPase.
abstract: OBJECTIVE
  There is limited data regarding the phenomenon of seasonal pseudohypokalemia. We aimed to demonstrate the incidence of spurious hypokalemia during the summer months and to investigate the mechanism of cause.
  
  
  METHODS
  Potassium and glucose results from primary care and hospital patients were collected retrospectively for a period of 1 year to assess the incidence of pseudohypokalemia. Experiments were undertaken to confirm that this was a reversible in vitro phenomenon due to increased temperature mediated by sodium-potassium-exchanging-ATPase.
  
  
  RESULTS
  Our data show an increased incidence of hypokalemia associated with increasing ambient temperature during June-August in samples from primary care but not in hospital samples. In a subset of patients, we showed that the repeat results were within or at the lower limit of the reference range. Experiments showed that this phenomenon was mediated by the sodium-potassium-exchanging-ATPase.
  
  
  CONCLUSIONS
  There is an increased incidence of pseudohypokalemia during the summer (seasonal pseudohypokalemia) in samples from primary care and this is an in vitro pseudo-phenomenon mediated by sodium-potassium-exchanging-ATPase.
authors.affiliation: Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital, Duncan Building, Prescot Street, Liverpool, L7 8XP, UK. ravsodi@yahoo.com
authors.forename: Ravinder
authors.initials: R
authors.lastname: Sodi
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Davison
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Holmes
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Hine
authors.forename: Norman B
authors.initials: NB
authors.lastname: Roberts
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D003981:Diazoxide / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007008:Hypokalemia / Q000097:blood* / Q000201:enzymology* / Q000378:metabolism; D049990:Membrane Transport Modulators / Q000494:pharmacology; D020110:Pinacidil / Q000494:pharmacology; D011188:Potassium / Q000097:blood; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013696:Temperature; D014044:Tolbutamide / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D049990:Membrane Transport Modulators; D020110:Pinacidil; D014044:Tolbutamide; D000254:Sodium-Potassium-Exchanging ATPase; D003981:Diazoxide; D011188:Potassium