| Year | No. of Samples tested | Result | ||
| Positive | Indeterminate | Discrepant | ||
| 2008 | 24125 | 2432 (10.08%) | 10 (0.04%) | 88 (0.37%) |
| 2009 | 23305 | 1923 (8.25%) | 6 (0.03%) | 73 (0.31%) |
| 2010 | 29460 | 1896 (6.43%) | 13 (0.04%) | 45 (0.15%) |
| 2011 | 29793 | 1757 (10.69%) | 19 (0.06%) | 37 (0.12%) |
| 2012 | 34613 | 1624 (4.69%) | 23 (0.07%) | 49 (0.14%) |
| Total | 141296 | 9632 (6.81%) | 71 (0.05%) | 292 (0.21%) |