Pseudo-hyperkalaemia in ambulatory samples: the never-ending story?

Hyperkalaemia is a major electrolyte disturbance, which can be life-threatening [1, 2]. Pseudo-hyperkalaemia has been described since 1955 but remains a frequent problem for clinicians, and is mainly linked to blood collection [3]. The pre-analytic phase is of particular relevance to avoid pseudo-hyperkalaemia generating useless treatments and hospitalizations. We conducted a study to determine the difference in hyperkalaemia prevalence in outpatient primary care between blood sampling performed at the laboratory versus at the patient's home. We conducted a retrospective analysis of all the blood samples with kalaemia measurement from January to December 2016 in a laboratory in the southeast of France (Draguignan). Samples taken at home were either delivered directly by the nurse to the laboratory for those taken in town, or to laboratory relay stations. The daily average temperature (the average of the 24-h temperatures) was provided by the national meteorological research centre. The...