Volume 27, Number 11—November 2021
Synopsis
Effectiveness of Abbott BinaxNOW Rapid Antigen Test for Detection of SARS-CoV-2 Infections in Outbreak among Horse Racetrack Workers, California, USA
Table 2
Results of BinaxNOW rapid antigen test compared with real-time reverse transcription PCR for coronavirus disease among all horse racetrack staff undergoing paired testing, California, USA, November–December 2020*
BinaxNOW result |
rRT-PCR result |
Total |
|
---|---|---|---|
Detected |
Not detected |
||
Round 1, n = 333, November 25, 27, 28† | |||
Detected | 40 | 0 | 40 |
Not detected | 58 | 235 | 293 |
Total |
98 |
235 |
333 |
Round 2, n = 197, December 4 | |||
Detected | 12 | 0 | 12 |
Not detected | 10 | 175 | 185 |
Total |
22 |
175 |
197 |
Round 3, n = 65, December 13 | |||
Detected | 2 | 0 | 2 |
Not detected | 3 | 60 | 63 |
Total |
5 |
60 |
65 |
Round 4, n = 57, December 16 | |||
Detected | 0 | 0 | 0 |
Not detected | 0 | 57 | 57 |
Total |
0 |
57 |
57 |
Round 5, n = 58, December 20 | |||
Detected | 0 | 0 | 0 |
Not detected | 1 | 57 | 58 |
Total |
1 |
57 |
58 |
Round 6, n = 59, December 22 | |||
Detected | 1 | 0 | 1 |
Not detected | 0 | 58 | 58 |
Total |
1 |
58 |
59 |
Overall, N = 769, November 25–December 22 | |||
Detected | 55 | 0 | 55 |
Not detected | 72 | 642 | 714 |
Total | 127 | 642 | 769 |
*Inconclusive (n = 4) and invalid (n = 3) rRT-PCR test results excluded from table. rRT-PCR, real-time reverse transcription PCR. †All employees who had not yet tested positive were meant to return for subsequent testing rounds. However, participant attrition occurred, likely because of employees leaving their jobs or logistical obstacles to being on-site for testing during mass testing days.