Performance characteristics of the cobas 4800 CT/NG test for urine and swab specimens
| Reference results: | cobas 4800 performance: | Additional cobas 4800 results: | ||||||||
| Pos (n) | Neg (n) | Sens (%) | Spec (%) | NPV (%) | PPV (%) | Failed, n (%) | Invalid, n (%) | |||
| C trachomatis | ||||||||||
| cobas 4800 | Urine (n=496) | Pos | 86 | 2 | 94.5 | 99.5 | 98.8 | 97.7 | 5 (1.0) | 3 (0.6) |
| Neg | 5 | 395 | ||||||||
| Swab (n=404) | Pos | 23 | 0 | 92.0 | 100 | 99.5 | 100 | 0 (0.0) | 1 (0.2) | |
| Neg | 2 | 378 | ||||||||
| N gonorrhoeae | ||||||||||
| cobas 4800 | Urine (n=318) | Pos | 13 | 0 | 92.9 | 100 | 99.7 | 100 | 4 (1.3) | 2 (0.6) |
| Neg | 1 | 298 | ||||||||
| Swab (n=180) | Pos | 9 | 1 | 100 | 99.4 | 100 | 90.0 | 0 (0.0) | 0 (0.0) | |
| Neg | 0 | 170 | ||||||||
Note: a total 900 specimens were investigated for C trachomatis and a subset of these (n = 498) were investigated for N gonorrhoeae.
Neg, negative; NPV, negative predictive value; Pos, positive; PPV, positive predictive value; Sens, sensitivity; Spec, specificity.