Table 3. Diagnostic performance of Standard ™ Q COVID-19 Ag test in different subgroups of participants
Features
Subgroup
RT-qPCR test
RT-qPCR test
Sensitivity% (CI*)
Specificity% (CI)
Accuracy%
Likelihood ratio
Standard ™ Q COVID-19 Ag test Positive Negative
Gender
Male (n = 49)
Positive
32
4
76.1 (0.61-0.86)
42.8 (0.27-0.64)
71.4
1.33
Negative 10 3
Female (n = 34)
Positive
22
1
78.5 (0.60-0.89)
83.3 (0.15-0.74)
79.4
4.71
Negative 5 5
Symptomatology (total n = 47) Symptomatic (n = 42)
Positive
32
0
76.1 (0.63-0.88)
NA
76.1
NA
Negative 10 0
Asymptomatic (n = 5)
Positive
2
1
66.6 (0.61-0.98)
50 (0-0.94)
60
0.66
Negative 1 1
Radiology (total n = 44) With findings (n = 37)
Positive
28
1
75.6 (0.59-0.86)
0 (0-0.94)
73.6
0.75
Negative 9 0
No findings (n = 7)
Positive
6
1
85.7 (0.48-0.95)
0 (0-1)
75
0.75
Negative 2 0
Days post symptom onset (total n = 69) *
0-7 (n = 38)
Positive
31
1
83.7 (0.68-0.92)
0 (0-0.94)
81.5
0.83
Negative 6 0
8-16 (n = 27) Positive 19 0 70 (0.51-0.84) NA 70.3 NA
Negative 8 0
>16 (n = 4) Positive 2 1 66.6 (0.11-0.98) 0 (0-0.94) 50 0.66
Negative 1 0