Big data analysis reveals the existence of seasonal pseudohyperkalaemia even in temperate climates.

Background: Seasonal pseudohyperkalaemia has been described in colder northern hemisphere countries. The lower temperatures may inhibit red cell Na-K-ATPase allowing the efflux of potassium and higher measured levels. It has not been described in warmer subtropical climates.
Aims: The aim was to determine if seasonal variation in serum potassium occurred in a temperate climate.
Methods: We conducted a retrospective review of serum potassium results over two years in two South African provinces with different microclimates and seasonal temperatures. The study included patient samples from surrounding clinics and hospitals in Pretoria, Gauteng province, and in Durban, KwaZulu-Natal province, South Africa. Average temperature ranges were obtained from the South African weather service from the same period (June 2015-June 2017).
Results: A total of 91,420 results were analysed and we found a statistically significant difference between the January (summer) and June (winter) serum potassium levels (p < .0001). These results demonstrate that the winter months in South Africa are associated with significantly higher measured potassium results.
Conclusion: Seasonal pseudohyperkalaemia may be more widespread than realized and can occur in more temperate climates and laboratories should take the appropriate action when transporting samples as this could influence interpretation and clinical management.
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