Influenza Research and Treatment

Research Article

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

Table 1

Comparison of early alert dates identified by statistical process control charts for full-season charting and modeled real-time charting of positive rapid influenza tests in the UUPCRN population for 4 seasons.


Influenza season	Date epidemic started	Full-season charting		Modeled real-time charting
Influenza season	Date epidemic started	Early alert* date relative to epidemic onset (days)	No. visits to trigger early alert* (% of visits)	Early alert^† date relative to epidemic onset (days)	No. visits to trigger early alert^† (% of visits)

2004-05	Jan 13	−13	2 (2.7%)	−17	2 (0.3%)
2005-06	Dec 13	−2	3 (3.6%)	−6	2 (0.2%)
2006-07	Feb 2	+2	2 (2.4%)	−15	4 (0.4%)
2007-08	Feb 3	−15	3 (2.4%)	−24	2 (0.2%)

Mean^‡ (sd)		−7.0 (8.3)		−15.5 (7.4)
Median		−7.5		−16.0

Early alert occurred on the date that rapid test positivity exceeded 3 sigma.
^†Early alert occurred on the date that rapid test positivity exceeded 3 sigma and did not return to the center line on the following day.
^‡One-sided t-test of means was significant (P = 0.039).