Percentage of blood laboratory samples for potassium determination drawn in the emergency department (ED) with hemolysis. INSTRUCTIONS: This measure is to be reported each time an ED patient having blood drawn for potassium determination during the performance period. This measure is an episode-of-care measure; the level of analysis for this measure is every potassium laboratory test during the measurement period. For example, for every laboratory test performed to evaluate a potassium level, the sample should be evaluated for hemolysis.