Evaluation of Three Automated Nucleic Acid Extraction Systems for Identification of Respiratory Viruses in Clinical Specimens by Multiplex Real-Time PCR
Table 3
Comparison of the PCR results from 3 automated nucleic acid extraction systems using a total of 84 nasopharyngeal specimens.
QIAcube
EZ1 advanced XL
MICROLAB Nimbus IVD
Positive results
45 (53.6%)
45 (53.6%)
43 (51.2%)
True positivea
42
38
41
False positivea (virus type)
3 (PIV4, EV, RSV-B)
7 (PIV1, ADV (), RSV-A, RV ())
2 (CoV-NL63, CoV-229E)
Negative results
39 (46.4%)
39 (46.4%)
41 (48.8%)
True negativea
36
34
35
False negativea (virus type)
3 (FluB, RV, ADV)
5 (BoV, RV ())
6 (FluB, RV, MPV, BoV, ADV ())
Sensitivity (%)
93.3
88.4
87.2
Specificity (%)
92.3
82.9
94.6
Concordance rate (%)
94.2
88.3
92.2
Kappa coefficientb (95% CI)
0.88 (0.79 to 0.97)
0.76 (0.64 to 0.89)
0.84 (0.74 to 0.95)
RV sensitivity/specificity
94.7/100.0
78.9/96.9
94.7/100.0
MPV sensitivity/specificity
100.0/100.0
100.0/100.0
85.0/100.0
PIV3 sensitivity/specificity
100.0/100.0
100.0/100.0
100.0/100.0
RSV-A sensitivity/specificity
100.0/100.0
100.0/98.7
100.0/100.0
ADV sensitivity/specificity
80.0/100.0
100.0/96.2
60.0/100.0
Characteristics of three systems
Principle
Spin column
Magnetic particle
Magnetic particle
Sample volume (L)
≤200
100–400
600
Elution volume (L)
20–150
60–150
100
Turnaround timec (min)
90
45
150
Sample capacity
12
14
48
Automated PCR set-up
Impossible
Impossible
Possible
When all three automated nucleic acid extraction systems yielded the same results, they were considered “true positive” or “true negative.” If only 1 system yielded negative result, it was considered “false negative.” When the pathogen was detected from only 1 system, multiplex PCR and sequencing analysis were performed to confirm the result. b for all values. cincludes lysis step but not the hands-on time.
