Background
Methods
Design and participants
Procedure and setting
Outcome variables
Laboratory tests
Test specifications | WANTAI SARS-CoV-2 Ab ELISA¥ | Quantitative anti-RBD ELISA (QRBD)€ | Chemiluminescence assay (CLIA) |
---|---|---|---|
Manufacturer | Beijing Wantai Biological Pharmacy Enterprise Co., Ltd, China | In-house kit developed by Translational Health Science And Technology Institute (THSTI), India | Abbott Laboratories Diagnostics, USA |
Principle | ELISA | ELISA | Chemi-luminiscence Assay |
Type | Qualitative | Quantitative | Qualitative |
Target protein | Receptor binding domain of spike protein | Receptor binding domain of spike protein | Nucleocapsid protein of SARS-CoV-2 |
Antibody captured | Total antibody (IgM + IgG + IgA) | IgG | IgG |
Test sensitivity | 94.5% | 100% | Unknown@ |
Test specificity | 100% | 100% | Unknown@ |
Reference Value | ≥ 0.19 OD = Positive < 0.19 OD = Negative | ≤ 7.99 BAU#/ml = Negative > 7.99—12.0 BAU#/ml = Equivocal ≥ 12.0 BAU#/ml = Positive | < 1.4 S/C$ = Negative ≥ 1.4 S/C$ = Positive |
Methodology for WANTAI SARS‐CoV‐2 Antibody ELISA
Methodology for QRBD
Methodology for CLIA
Data analysis
Results
Variables | Category | Urban (n = 1700) n (%) | Rural (n = 1791) n (%) |
---|---|---|---|
Age | < 18 years | 157 (9.3) | 331 (18.5) |
≥ 18 years | 1543 (90.7) | 1460 (81.5) | |
Sex | Male | 699 (41.1) | 839 (46.8) |
Female | 1001 (58.9) | 952 (53.2) | |
Vaccination | Vaccinated | 98 (5.7) | 273 (15.2) |
Un-vaccinated | 1599 (94.0) | 1518 (84.7) | |
Unknown | 3 (0.2) | 0 |
Test | Positive n (%) | Negative n (%) |
---|---|---|
WANTAI (n = 3491) | 2725 (78.1) | 766 (21.9) |
QRBD (n = 3357)* | 2524 (75.2) | 833 (24.8) |
CLIA (n = 3491) | 1110 (31.8) | 2381 (68.2) |
Test Name | WANTAI | Test accuracy of QRBD (95% CI) | Total agreement | Kappa (SE, 95% CI) | |||
---|---|---|---|---|---|---|---|
Positive | Negative | Total | |||||
QRBD | Positive | 2482 (98.3) | 42 (1.6) | 2524 (100.0) | Sensitivity: 94.6% (93.6–95.4%) Specificity: 94.3% (92.3–95.8%) | 94.5% | 0.84 (SE = 0.018) (95% CI 0.80–0.87) |
Negative | 142 (17.1) | 691 (82.9) | 833 (100.0) | ||||
CLIA | Positive | 1098 (98.9) | 12 (1.1) | 1110 (100.0) | Sensitivity: 40.3% (38.4–42.2%) Specificity: 98.4% (97.3–99.2%) | 53.1% | 0.22 (SE = 0.011) (95% CI 0.19–0.24) |
Negative | 1627 (68.3) | 754 (31.7) | 2381 (100.0) |
Test name | QRBD | Test accuracy of CLIA (95% CI) | Total agreement | Kappa (SE, 95% CI) | |||
---|---|---|---|---|---|---|---|
Positive | Negative | Total | |||||
CLIA | Positive | 1084 (99.2) | 8 (0.8) | 1092 (100.0) | Sensitivity: 42.9% (41.0–44.9%) Specificity: 99.0% (98.1–99.5%) | 56.8% | 0.26 (SE = 0.012) (95% CI 0.23 -0.28) |
Negative | 1440 (63.6) | 824 (36.4) | 2264 (100.0) |
Test | Vaccinated (n = 371) | Unvaccinated (n = 3117) | ||
---|---|---|---|---|
Total | Single dose (n = 284) | Two doses (n = 87) | ||
Wantai | 292 (78.1%) | 207 (72.9%) | 85 (97.7%) | 2431 (77.9%) |
QRBD | 269 (76.8%) (n = 350)# | 190 (71.9) (n = 264)$ | 79 (91.6%) (n = 86)@ | 2253 (75.1%) (n = 3001)θ |
CLIA | 151 (40.7%) | 102 (35.9%) | 48 (55.2%) | 958 (30.7%) |