BioSense is an all-hazards surveillance program for achieving near real-time national public health situation awareness and early detection. Prospective anomaly detection methods such as the Modified EARS C2 are commonly adapted and used in BioSense and other public health syndromic surveillance systems. These methods however can produce an excessive false alert rate. Analyses results will be presented on the combined use of retrospective (e.g., Change Point Analysis (or CPA)) and prospective (e.g., C2) anomaly detection methods. This combined approach will help detect sudden aberrations in addition to subtle changes in local trends, help rule out alarm investigations, and assist with retrospective follow-ups. Examples on the utility of this combined approach in working collaboratively with the scientific community are applied to BioSense emergency departments' visits due to ILI. Methods, limitations, future work, and invitation to the scientific community to collaborate with us will be discussed at this talk.