BioSense and Louisiana influenza-like-illness, gastrointestinal, and upper respiratory syndrome classifications were applied to Louisiana emergency department data to examine if varying syndrome definitions yield similar results when applied to the same data. Results were highly correlated for each syndrome pair however syndrome percentage means were significantly different. Most C2 alerts occurred on corresponding weeks, providing confidence in the use of C2 on current syndrome definitions for aberration detection. As public health jurisdictions work towards developing common syndrome classifications for comparability across jurisdictions, this analysis provides evidence that current differences in syndrome definitions may not hinder comparability of trends over time.