Development and Validation of an ELISA at Acidic pH for the Quantitative Determination of IL-13 in Human Plasma and Serum
Table 4
Selectivity assessment of IL-13 assay in human plasma under acidic conditions. 25.0 pg/mL of recombinant IL-13 was spiked in the same 6 plasma samples tested for parallelism. Accuracy was calculated using the IL-13 concentration determined at dilution 1 : 2 as a reference value. Selectivity was considered acceptable when accuracy was between 70 and 130% for at least 5/6 samples at each dilution.
Dilution
Raw result (pg/mL)
Accuracy (/, %)
Observed ()
Expected ()
Sample 1
1 : 2
14.11
1 : 3
9.36
9.41
99.5
1 : 4
7.70
7.06
109.1
1 : 12
2.42
2.35
102.8
1 : 36
0.80
0.78
102.5
Sample 2
1 : 2
13.99
1 : 3
9.64
9.32
103.4
1 : 4
7.25
6.99
103.6
1 : 12
2.48
2.33
106.4
1 : 36
0.85
0.78
109.5
Sample 3
1 : 2
11.12
1 : 3
8.28
7.41
111.7
1 : 4
6.47
5.56
116.4
1 : 12
2.45
1.85
132.2*
1 : 36
0.85
0.62
137.2*
Sample 4
1 : 2
15.17
1 : 3
9.89
10.11
97.8
1 : 4
7.46
7.59
98.4
1 : 12
2.54
2.53
100.5
1 : 36
0.86
0.84
101.9
Sample 5
1 : 2
14.87
1 : 3
10.07
9.91
101.6
1 : 4
7.50
7.43
100.8
1 : 12
2.69
2.48
108.4
1 : 36
0.99
0.83
119.4
Sample 6
1 : 2
13.16
1 : 3
8.96
8.77
102.2
1 : 4
6.78
6.58
103.0
1 : 12
2.27
2.19
103.4
1 : 36
N.R.
N.R.
N.R.
N.R.: not reported due to a technical issue.
*Value outside acceptance criteria.
