NC DETECT emergency department (ED) data were analyzed to assess the impact of applying the BioSense 24-hour rule that combines ED visits into a single visit if the patient ID and facility ID are the same and the earliest recorded times occur within the same 24-hour time frame. 4,822,347 unique ED visits from 2013 NC DETECT data were included in this analysis. Applying the 24-hour rule reduced the overall ED visit count in NC by approximately 1.7%. The percentage of ED visits lost was higher for certain types of visits, e.g. behavioral health, healthcare utilization, GI illness and varied significantly across counties in NC.