Point-of-Care Testing as an Influenza Surveillance Tool: Methodology and Lessons Learned from Implementation

Figure 2

Statistical process control chart* of modeled real-time surveillance of positive influenza rapid tests demonstrating an early alert in the UUPCRN population for the 2007-08 season. *Solid horizontal line defines the center line. Dashes above each data point represent the upper control limit calculated for that day. Points exceeding the upper control limit are noted by “A.” The modeled real-time surveillance alert (Jan 10) was defined as the date for the data point following an exceedance of the upper control limit (A) that does not subsequently return to the center line.