Table 3. Data showing match of Air Force respiratory virus specimens to ICD-9 coded visits, January 2002–July 2003*.

No. visits/type	No. specimens
2 visits recorded (n = 321)
Both non-ILI	90
1 ILI; 1 non-ILI	164
Both ILI	67
3 visits recorded (n = 12)
3 non-ILI	6
1 ILI; 2 non-ILI	5
2 ILI; 1 non-ILI	1
4 visits recorded (n = 1)
1 ILI; 3 non-ILI	1

*ICD-9, International Classification of Diseases, Ninth Revision; ILI, influenza-like illness.
†No. specimens obtained by day of matching visit.