TABLE 1

Antigen-detecting RDT results with a supervised self-collected anterior nasal (AN) swab and with a professional-collected nasopharyngeal (NP) swab in RT-PCR positive patients from combined oro-/nasopharyngeal swab

No.AN swab self-collected sd Q Ag-RDTNP swab prof.-collected sd Q Ag-RDTOP/NP swab RT-PCRSymptom duration (days)
CT valueViral load+
1pos (+++)pos (+++)17.33#9.592
2pos (++)pos (+++)17.86#9.431
3pos (+++)pos (+++)18.01#9.381
4pos (++)pos (+++)18.31#9.293
5pos (+++)pos (+++)18.40#9.273
6pos (+++)pos (+++)18.76#9.164
7pos (+++)pos (+++)18.77#9.165
8pos (+++)pos (+++)18.78#9.165
9pos (+++)pos (+++)19.05#9.083
10pos. (+++)pos. (+++)19.40#8.972
11neg.pos (+++)19.66#8.901
12pos (+++)pos (+++)20.32#8.703
13pos (+++)pos (+++)17.818.684
14pos (++)pos (+++)20.44#8.672
15pos (++)pos (++)20.54#8.635
16pos (+++)pos (+++)21.09#8.474
17pos (+++)pos (+)18.628.444
18pos (+)pos (++)21.87#8.247
19pos (++)pos (+++)19.348.235
20pos (++)pos (+++)22.05#8.192
21pos (+++)pos (+++)19.478.196
22pos (+++)pos (+++)22.60#8.036
23pos (+++)pos (++)23.66#7.716
24pos (+)pos (++)26.42#6.905
25pos (+++)pos (+++)26.77#6.795
26neg.neg.24.256.7810
27pos (++)pos (+++)24.776.624
28pos (+++)pos (++)25.296.462
29pos (+)pos (++)29.33#6.035
30neg.neg.29.56#5.973
31neg.neg.29.95#5.853
32pos (+)pos (+)30.25#5.764
33neg.neg.27.815.728
34pos (++)pos (+)31.20#5.488
35neg.pos (+)31.61#5.3610
36neg.neg.32.58#5.0710
37neg.neg.32.86#4.992
38neg.neg.34.62#4.477
39neg.neg.35.53#4.2014
Sensitivity
29/39 (74.4%)
Sensitivity
31/39 (79.5%)
Positive percent agreement§
90.6% (CI 75.8–96.8)

CT-values and viral load (in descending order) of the paired RT-PCR samples are shown, as well as the duration of symptoms per patient. The positive percent agreement between AN and NP samples on Ag-RDT, as well as the respective sensitivities compared to RT-PCR are shown.

Abbreviations: No.: patient number; sd Q: STANDARD Q COVID-19 Ag Test (sd Biosensor); Ag-RDT: antigen-detecting rapid diagnostic test; AN: anterior nasal; NP: nasopharyngeal; OP: oropharyngeal; CT: cycle threshold; RT-PCR: reverse transcription-polymerase chain reaction; neg.: negative; pos (+): weak positive; pos. (++): positive; pos. (+++): strong positive.

#Roche Cobas SARS-CoV-2 assay (E-gene, T2 target).

TibMolbiol assay, E-gene target.

+log10 RNA SARS-CoV2/swab.

§including 2 false positives on AN and 1 on NP.