TABLE 1.
3Flex MFI values of pre-COVID-19 serum, including serum positive for potential cross-reactivitya
| Sample group | n | MFI avg (95% CI) |
||
|---|---|---|---|---|
| Spike | RBD | Nucleocapsid | ||
| Otherb | 93 | 140 (127–153) | 91 (88–93) | 224 (159–288) |
| Lyme disease | 10 | 148 (138–157) | 97 (92–102) | 564 (58–1,069) |
| Syphilis | 10 | 165 (148–182) | 105 (98–113) | 214 (3–284) |
| CMV | 10 | 180 (113–247) | 96 (91–102) | 230 (99–361) |
| EBV/Mono | 10 | 187 (134–241) | 109 (102–117) | 265 (165–365) |
| Acute viral respiratory illness | 55 | 136 (121–151) | 91 (90–93) | 165 (107–223) |
| ANA | 20 | 178 (153–202) | 101 (97–104) | 348 (162–535) |
| Rheumatoid factor | 10 | 149 (134–164) | 99 (94–104) | 476 (80–873) |
a
Abbreviations: 95% CI, 95% confidence interval; ANA, antinuclear antigen; CMV, cytomegalovirus; EBV/Mono, Epstein-Barr virus mononucleosis; MFI, median fluorescent intensity.
b
Samples with no serological diagnosis.