Id |
Subject |
Object |
Predicate |
Lexical cue |
T92 |
0-171 |
Sentence |
denotes |
To obtain a preliminary assessment of analytical sensitivity, we used purified cell culture supernatant containing SARS-CoV strain Frankfurt-1 virions grown on Vero cells. |
T93 |
172-284 |
Sentence |
denotes |
The supernatant was ultrafiltered and thereby concentrated from a ca 20-fold volume of cell culture supernatant. |
T94 |
285-424 |
Sentence |
denotes |
The concentration step simultaneously reduces the relative concentration of background nucleic acids such as not virion-packaged viral RNA. |
T95 |
425-584 |
Sentence |
denotes |
The virion preparation was quantified by real-time RT-PCR using a specific in vitro-transcribed RNA quantification standard as described in Drosten et al. [8]. |
T96 |
585-743 |
Sentence |
denotes |
All assays were subjected to replicate testing in order to determine stochastic detection frequencies at each assay’s sensitivity end point (Figure 3A and B). |
T97 |
744-918 |
Sentence |
denotes |
All assays were highly sensitive, with best results obtained for the E gene and RdRp gene assays (5.2 and 3.8 copies per reaction at 95% detection probability, respectively). |
T98 |
919-971 |
Sentence |
denotes |
These two assays were chosen for further evaluation. |
T99 |
972-1176 |
Sentence |
denotes |
One of the laboratories participating in the external evaluation used other basic RT-PCR reagents (TaqMan Fast Virus 1-Step Master Mix) and repeated the sensitivity study, with equivalent results (E gene: |
T100 |
1177-1209 |
Sentence |
denotes |
3.2 RNA copies/reaction (95% CI: |
T101 |
1210-1225 |
Sentence |
denotes |
2.2–6.8); RdRP: |
T102 |
1226-1258 |
Sentence |
denotes |
3.7 RNA copies/reaction (95% CI: |
T103 |
1259-1268 |
Sentence |
denotes |
2.8–8.0). |
T104 |
1269-1433 |
Sentence |
denotes |
Of note, the N gene assay also performed well but was not subjected to intensive further validation because it was slightly less sensitive (Supplementary Figure S2) |