Supplementary
Information
p.1
Supplemental Information for:
Laboratory Evaluation Links Some False-positive COVID-19 Antigen Test
Results Observed in a Field Study
to a Specific Lot of Test Strips
Alyssa M. Carter
1#
, Alexander V
iloria Winnett
1#
, Anna E. Romano
1
, Reid Akana
1
, Natasha Shelby
1
,
Rustem F. Ismagilov
1*
1
California Institute of Technology, Pasadena, CA
*Corresponding author:
rustem.admin@caltech.edu
; (626) 395-8130; alternate corresponding author:
tshelby@caltech.edu
; (626) 395-2333
#
These authors contributed e
qually to this manuscript
Contents:
1.
Supplementary Table 1
2.
Contribution Statements for Non-Corresponding Authors
Supplementary
Information
p.2
Supplementary Table 1. Complete laboratory
evaluation of Ag-RDT test strips.
Each trial of the laboratory
evaluation assesses one Ag-RDT strip, listed with the corr
esponding lot number. SARS-CoV-2 concentration is the
number of SARS-CoV-2 copies/mL of the test buffer wh
en contrived specimens are applied (see methods). The
incubation time is defined as the difference between the time at
which the strip was taken out of the test buffer and the
time at which the strip was placed in the
buffer. The read window is defined as th
e difference between the time at which
the last reader interpreted the results of the test and the tim
e at which the strip was taken out of the buffer. The anticipate
d
result for each trial is based off the concentration of particl
es applied to each strip. The th
ree reads for each trial are lis
ted
and positive results are highlighted in red. The proportion of
reads called positive is also listed, and any percentage above
0% when the anticipated result was ne
gative is also highlighted in red.
Trial
Antigen Test Lot
Number
SARS-CoV-2 Concentration
Spike-in (copies/mL)
Incubation
Time
Read
Window
Anticipated
Result
Reader 1
Reader 2
Reader 3
% Called
Positive
1
152194
Quidel Positive Control Swab
11 min
2 min
Positive
Positive
Positive
Positive
100
2 152194
2.0x10
6
copies/mL
10 min
3 min
Negative
Negative
Negative
Negative
0
3
152194
4.0x10
6
copies/mL
10 min
3 min
Negative
Negative
Negative
Negative
0
4 152532
1.0x10
7
copies/mL
10 min
3 min
Positive
Positive
Positive
Positive
100
5
152532
1.3x10
7
copies/mL
10 min
3 min
Positive
Positive
Positive
Positive
100
6 152194
1.5x10
7
copies/mL
10 min
3 min
Positive
Negative
Positive
Positive
66.7
7
152194
0 copies/mL
11 min
2 min
Negative
Negative
Negative
Negative
0
8
152194
0 copies/mL
10 min
2 min
Ne
gative Negative Negative Negative 0
9
152194
0 copies/mL
10 min
4 min
Negative
Negative
Negative
Negative
0
10
152194
0 copies/mL
11 min
3 min
Negative Negative Negative Negative 0
11
000202
0 copies/mL
10 min
2 min
Negative
Negative
Negative
Negative
0
12
000202
0 copies/mL
10 min
2 min
Negative Negative Negative Negative 0
13
000202
0 copies/mL
11 min
2
min
Negative
Negative
Negative
Negative
0
14
000202
0 copies/mL
10 min
2 min
Negative Negative Negative Negative 0
15
000202
0 copies/mL
11 min
3 min
Negative
Negative
Negative
Negative
0
16
152000
0 copies/mL
10 min
3 min
Negative
Positive
Positive
Negative
66.7
17
152000
0 copies/mL
10 min
3 min
Negative
Positive
Positive
Negative
66.7
18
152000
0 copies/mL
10 min
4 min
Negative
Positive
Positive
Negative
66.7
19
152000
0 copies/mL
10 min
3 min
Negative
Positive
Positive
Positive
100
20
152000
0 copies/mL
10 min
4 min
Negative
Positive
Positive
Positive
100
21
152000
0 copies/mL
10 min
4 min
Negative
Positive
Positive
Invalid
66.7
22
152532
0 copies/mL
10 min
4 min
Negative Negative Negative Negative 0
23
152532
0 copies/mL
10 min
2 min
Negative
Negative
Negative
Negative
0
24
152532
0 copies/mL
10 min
3 min
Negative Negative Negative Negative 0
Supplementary
Information
p.3
Contribution Statements for
Non-Corresponding Authors:
Reid Akana (RA) - Reader for laboratory evaluation bli
nded to experimental conditions. Wrote Python function to
perform statistical testing. Reviewed manuscript draft.
Alyssa M. Carter (AMC) - Designed laboratory evaluation. Op
erator for laboratory evaluation. Reported issue with lot
152000 to Quidel and interacted with Quidel representativ
es. Outlined and co-wrote manuscript with AVW. Analyzed
field study and laboratory evaluation data with AVW. Drafte
d Figure 1 with AVW. Prepared Supplementary Table 1.
Major contributor to selection of references for manuscript with AVW
Anna E. Romano (AER) – Reviewed partic
ipant Ag-RDT photos from field evaluation to extract strip lot information.
Performed interim analysis of Ag-RDT results by strip lot.
Provided feedback on design of laboratory evaluation. Reader
for laboratory evaluation blinded to experiment
al conditions. Reviewed manuscript draft.
Natasha Shelby (NS) - Study administrator. Interviewed a
ll participants who received
false-positive antigen results.
Amended IRB protocol to add acquis
ition of antigen lot numbers. Filed Me
dline FDA report about lot #152000 and
interacted with Quidel representatives. QC of data. Reader
for laboratory evaluation blinde
d to experimental conditions.
Reviewed and edited manuscript draft.
Alexander Viloria Winnett (AVW) – Provided feedback on d
esign of laboratory evaluation. Reader for laboratory
evaluation blinded to experimental conditions Reported issue
with lot 152000 to Quidel and interacted with Quidel
representatives. Major contributor to selection of referen
ces for manuscript with AMC. Managed reference library.
Outlined and co-wrote manuscript with
AMC. Analyzed field study and laborator
y evaluation data with AMC. Drafted
Figure 1 with AMC.