Table 2.

Limit of detection levels for HPV16 and HPV18

Cells/ml	SiHa (HPV16)		HeLa (HPV18)
	No. positive/No. test	Mean ± SD Cta	No. positive/No. test	Mean Ct
10,000	6/6	31.4  ±  0.2	6/6	28.7  ±  0.2
2000	6/6	33.9  ±  0.2	6/6	31.4  ±  0.3
400	6/6	36.7  ±  0.4	6/6	34.2  ±  0.3
80	6/6#	38.7  ±  0.4	6/6	36.5  ±  0.5
16	1/6	40.4	6/6#	39.7  ±  0.3
3	0/6	NA	1/6	38.9
0	0/6	NA	0/6	NA

^aCt cycle threshold, NA not applicable

^#The lowest concentration in which all the 6 replicates tested as positive for each cell line