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.
