A full incremental analysis was undertaken and five strategies remained relevant. In descending order of incremental cost effectiveness ratio these were:
1) no chest x-ray, single-step QFN-GIT at 250/100,000 with an ICER of £21,565.30 per active TB case averted
2) no chest x-ray, single-step QFN-GIT at 150/100,000 with an ICER of £31,867.1 per active TB case averted
3) no chest x-ray, single-step QFN-GIT at 40/100,000 with an ICER of £34,753.50 per active TB case averted
4) chest x-ray at port-of-arrival, single-step QFN-GIT at 40/100,000 with an ICER of £59,489.10 per active TB case averted
5) chest x-ray, single-step T-SPOT.TB at 40/100,000 with an ICER of £402,421.80 per active TB case averted
Sensitivity analysis showed that the results were sensitive to a range of parameters. ICERs were negatively affected and rankings altered when test specificities were reduced, the proportion of immigrants commencing and completing chemoprophylaxis was reduced and screening costs were increased.