2018 Volume 67 Issue 4 Pages 512-518
Potassium is one of the most frequently analyzed elements in the body. It plays a clinical role in homeostasis, and hyperkalemia is a common electrolyte disorder. In the laboratory, hemolysis increases serum potassium levels and causes pseudohyperkalemia. Therefore, the determination of potassium levels using nonhemolyzed samples is recommended. However, sometimes, blood re-collection is difficult. Thus, our purpose is to develop a potassium-compensating equation to minimize the need for blood re-collection. We manufactured a hemolysis reproduction reagent from heparinized blood samples from fifty patients. We added this reagent into pooled serum and reproduced the hemolyzed samples. We determined the potassium levels and hemolysis indices of these hemolyzed samples. Using these results, we developed two compensating equations, namely, equations 4 and 5. Then, we verified the accuracies of these equations. For this verification test, serum samples from forty patients whose blood was collected twice because the first sample was hemolyzed were used. We compared the potassium levels of nonhemolyzed samples with the compensated potassium levels of hemolyzed samples. Equation 4 is not useful because the differences were large. On the other hand, equation 5 can compensate for potassium levels with differences of approximately 0.3 mmol/L. We can estimate the true potassium levels using equation 5, even when the samples are hemolyzed.
