The impact of centrifugation in primary care on pseudohyperkalaemia: a retrospective evaluation

Spurious hyperkalaemia is a relatively common occurrence in samples originating from primary care. Failure to identify spurious hyperkalaemia carries a significant risk of patient mismanagement. We have carried out a retrospective evaluation to review the impact of the use of centrifuges in primary care for biochemistry blood samples on the management of hyperkalaemia.

Serum potassium concentrations in samples received from primary care were reviewed for six months prior to and after the implementation of on-site centrifugation. Samples exhibiting significant hyperkalaemia (serum potassium >6.0 mmol/L) were further investigated to ascertain the degree of patient follow-up.

There was a significant decrease in the number of samples exhibiting marked hyperkalaemia following the implementation (2244 versus 524; P < 0.0001). In terms of patient follow-up, we observed a reduction in the number of patients exhibiting pseudohyperkalaemia that previously had led to inappropriate hospital admissions over the same time period (6 cases postimplementation versus 22 cases preimplementation). We also observed an increase in the number of patients exhibiting true hyperkalaemia during the six-month period postimplementation (33 cases postimplementation versus 6 cases preimplementation).

The centrifugation of serum samples in primary care improves the sample quality and the integrity of the potassium results reported. We have also demonstrated evidence of an improvement in patient management and quality of care.