Table 2.

Linearity test.

Sample concentration	The value of T	The value of C	Characteristic value
100 ng/ml	13392	20244	0.661529362
10 ng/ml	2747	26454	0.103840627
1 ng/ml	442	35354	0.012502122
0.1 ng/ml	193	36069	0.005350855
0.05 ng/ml	318	39575	0.008035376
0	292	26233	0.011131018