TABLE 3.

Comparison of AG-CCA and conventional TC for detection of enterovirus in clinical specimens^a

No. of days (h) to TC isolation	Cumulative no. positive		% Positive
	Ag-CCA	TC-CPE	Ag-CCA	TC-CPE
1 (24)	17	0	33	0
2 (48)	31	6	62b	12c
3 (72)	37d	12	73	23
4 (96)	46	23	90	42
5 (120)	47	27	92	52
6 (144)	NDe	32	ND	62
7 (168)	ND	38	ND	73
8 (192)	ND	42	ND	81
9 (216)	ND	47	ND	90
≥10 (≥244)	ND	51	ND	98

^aAmong 273 specimens tested during the 1999 enterovirus season, 51 (19%) were resolved as true positives by Ag-CCA and TC-CPE. The date to tube culture isolation was tabulated from the date of culture (IFA) confirmation. Approximately 10 specimens required subpassage, thereby delaying the TC isolation final report by ∼24 h. 

^bSensitivity (after 48 h), 62%; specificity, 100%; PPV, 100%; NPV, 93%. 

^cSensitivity (after 48 h), 12%; specificity, 100%; PPV, 100% NPV, 85%. 

^dSpecimens negative after 24 or 48 h only were tested for an additional 3 days by Ag-CCA. After 120 h, Ag-CCA sensitivity and specificity were and 98%, respectively. 

^eND, not done.