Pseudohyperkalaemia at commercial laboratories in Japan: a questionnaire survey

Abstract

Background: Pseudohyperkalaemia caused by recentrifugation after storage or delay in separation of serum from blood cells is not uncommon. The purpose of this study was to audit pseudohyperkalaemia at commercial laboratories in Japan. Methods: A questionnaire asking about how samples are handled for potassium measurement and information on pseudohyperkalaemia was sent to 431 commercial laboratories. Results: A total of 263 (response rate 61%) questionnaires were returned and suitable for analysis. Pseudohyperkalaemia caused by recentrifugation was seen at 145 (70%) laboratories. Pseudohyperkalaemia caused by delay in separation of serum was also seen in many laboratories. Blood samples were centrifuged on site in only 46% of hospitals and in 17% of clinics served by these laboratories. The longest average time from venesection to centrifugation was 18 h. Although half the laboratories had asked their client facilities to centrifuge blood samples on site, very few complied. Conclusion: Pseudohyperkalaemia is not uncommon at commercial laboratories in Japan. Further efforts are necessary to avoid inappropriate handling at blood collection sites and in laboratories.