This study was done to analyze the relation between potassium levels (K) and hemolysis index (HI). A different method for this kind of study -cluster analysis- was used to classify data, according to its hemolysis level. 5 clusters were obtained as a result of the cluster analysis using the absolute differences of first and last K and HI values. Regression analysis was used to understand impact of the hemolysis on K levels at each of 5 different clusters. Results which had HI difference values higher than 295 mg/dL were showed a very high correlation with K. © 2013 Springer-Verlag.