A Comparative Study for Detection of EGFR Mutations in Plasma Cell-Free DNA in Korean Clinical Diagnostic Laboratories
Table 4
The performance of interlaboratory comparison samples using the cobas EGFR Mutation Assay.
Sample
p.L858R
p.E746_A750del (exon 19 deletion)
p.T790M
p.A767_V769dup (exon 20 insertion)
Expected allele frequency (%
Copies of mutant DNA (/μL
Mean
SD
CV (%)
Expected allele frequency (%
Copies of mutant DNA (/μL
Mean
SD
CV (%)
Expected allele frequency (%
Copies of mutant DNA (/μL
Mean
SD
CV (%)
Expected allele frequency (%
Copies of mutant DNA (/μL
Mean
SD
CV (%)
Level 1
4.29
760
9.91
0.61
6.16
5.19
600
15.14
0.27
1.79
4.01
420
11.28
0.5
4.43
3.85
362
4.52
0.25
5.57
Level 2
4.02
380
8.65
0.5
5.76
4.72
300
14.24
0.18
1.29
3.61
210
10.25
0.59
5.74
3.42
181
3.56
0.47
13.1
Level 3
0.8
140
6.93
0.47
6.79
1.1
108
12.03
0.56
4.63
0.81
72
7.4
1.78
24.08
0.72
62
2.07
0.64
30.98
Level 4
0.12
20
-
-
-
0.1
10
8.91
0.63
7.11
0.11
10
-
-
-
0.05
4
-
-
-
Precision materials (P-1~P-3
3.0
NP
9.99
0.46
4.61
3.0
NP
15.2
0.27
1.78
3.0
NP
11.03
0.31
2.83
-
-
-
-
-
3.0
NP
9.77
0.53
5.46
3.0
NP
15.2
0.3
1.95
3.0
NP
11.22
0.49
4.38
-
-
-
-
-
3.0
NP
9.75
0.72
7.35
3.0
NP
15.22
0.32
2.09
3.0
NP
11.19
0.59
5.24
-
-
-
-
-
allelic frequency and copies of mutant DNA in materials were adjusted using next-generation sequencing result from information provided by the manufacturer of reference standards. positive results from precision materials were summarized in the table. SQI, semiquantitative index; SD, standard deviation; CV, coefficient of variation; NP, not provided.
