Definitions of classifications used for LTBI, hepatitis B, hepatitis C and HIV
| Infection (number screened) | Classification status | Definition | Number classified (%*) |
| Latent tuberculosis (n=489)† | Positive‡ | TB-specific antigen response >0.35 IU/mL and no evidence of active disease on clinical assessment | 81 (16.5) |
| Negative | TB-specific antigen response <0.35 IU/mL | 408 (83.1) | |
| Hepatitis B (n=489)† | Current | HBsAg positive, anti-HBc negative, anti-HBs negative | 7 (1.4) |
| Past | HBsAg negative, anti-HBc positive, anti-HBs positive (confirmed; n=43) Or HBsAg negative, anti-HBc positive, anti-HBs negative (probable past; n=8) | 51 (10.4) | |
| Immune probably through vaccination§ | HBsAg negative, anti-HBc negative¶, anti-HBs positive | 140 (28.7) | |
| Non-immune | HBsAg, anti-HBc, anti-HBs negative | 291 (59.5) | |
| Hepatitis C (n=491) | Current | Anti-HCV positive and HCV RNA positive | 51 (10.4) |
| Past | Anti-HCV positive, HCV RNA negative and RIBA positive | 13 (2.7) | |
| Uncertain history | Anti-HCV positive or equivocal, HCV RNA negative and no RIBA or insufficient sample for testing | 3 (0.6) | |
| Negative | Anti-HCV and HCV RNA negative | 424 (86.4) | |
| HIV (n=491) | Seropositive | Anti-HIV/p24 antigen positive | 5 (1.0) |
| Seronegative | Anti-HIV/p24 antigen positive | 486 (99.0) |
↵*Denominator for each percentage is number screened, in first column.
↵†Two missing LTBI results as indeterminate and two missing hepatitis B test results due to insufficient sample for testing.
↵‡Further details available from Cellestis, Australia, including interpretation of controls.34
↵§Median anti-HBs level was 195 IU/L (IQR 46–945).
↵¶Three subjects had equivocal anti-HBc and negative anti-HBe.
HBc, hepatitis B core; HBe, hepatitis B envelope; HBs, hepatitis B surface; HBsAg, hepatitis B surface antigen; HCV, hepatitis C virus; LTBI, latent tuberculosis infection; RIBA, Recombinant ImmunoBlot Assay.