TABLE 2.
CrAg LFA titers for each semiquantitative interpreted value
| Novel CrAg assay | Result | No. of specimens | Titer obtained with IMMY CrAg LFAa
|
|
|---|---|---|---|---|
| Median | IQR | |||
| IMMY CrAgSQ | False negative | 1 | <1:5 | |
| 1+ | 8 | 1:5 | 1:5–1:20 | |
| 2+ | 23 | 1:40 | 1:20–1:160 | |
| 3+ | 11 | 1:320 | 1:40–1:2,560 | |
| 4+ | 11 | 1:640 | 1:80–1:5,120 | |
| 5+b | 0 | |||
| Biosynex CryptoPS | False negative | 7 | 1:5 | 1:5–1:20 |
| Positive | 28 | 1:40 | 1:20–1:320 | |
| Strong Positive | 19 | 1:320 | 1:80–1:5,120 | |
a
The IMMY CrAg LFA is the U.S. Food and Drug Administration (FDA)-approved reference assay. LFA, lateral flow assay; IQR, interquartile range.
b
No CrAgSQ 5+ readings were observed in our testing, which would occur if there was a potential prozone effect.