Details of N gonorrhoeae test results for the 34 discordant specimens
| No of specimens | LDQA screen | COBAS screen | Additional tests | ‘Resolved’ NG result | |||
| LDQA NG | LDQA NG result | COBAS NG Amplicor* | NSppID | NG-OPA | NG culture | ||
| porA | Methyltransferase | 16s rDNA | opa | ||||
| (# Female) | (CP range) | (Melt temp)† | (CP range) | ||||
| 3 (3) | − | − | Grey zone | − | − | − | − |
| 3 (3) | − | − | Grey zone | 56°C, 65°C | − | − | − |
| 18 (9) | − | − | Inhibitory | − | − | − | − |
| 1 (0) | 22 | NG DNA detected | Inhibitory | − | 22 | −‡ | NG positive |
| 1 (0) | 25 | NG DNA detected | Inhibitory | 60°C | 23 | −‡ | NG positive |
| 1 (0) | 23 | NG DNA detected | Inhibitory | 60°C | 23 | NG isolated | NG positive |
| 3 (3) | 28–40 | NG DNA detected | NG DNA detected | − | 28–38 | NG isolated | NG positive |
| 3 (2) | − | − | NG DNA detected | − | − | − | − |
| 1 (1) | − | − | NG DNA detected | 65°C | − | − | − |
| Total 34 (21) | |||||||
Results for all other specimens were concordant. Resolved results were used in LDQA kappa analysis.
−, Negative; CP, real-time PCR crossing point; NG, N gonorrhoeae.
Results for the remaining 11 NG resolved positives were concordant.
↵* COBAS NG Amplicor defined grey zone results as optical density (OD) between 0.300 to 0.999 and positive results if OD ≥1000. COBAS CT Taqman does not give grey zone results.
↵† N gonorrhoeae was defined by a melt temperature of 60°C. Melt temperatures other than 60°C were indicative of other Neisseria spp.
↵‡ N gonorrhoeae not isolated but Gram-negative diplococci were observed when cells were stained directly from the specimen swab.