Table 5.

Conversion and reversion rates at each follow-up, using different conversion definitions.

Conversion definition*	6 month	12 month	18 month
A	18/159 (11.3%)	16/143 (11.2%)	29/139 (20.9%)
B	11/159 (6.9%)	11/143 (7.7%)	20/139 (14.4%)
C	10/159 (6.3%)	10/143 (7%)	16/139 (11.5%)
Reversion**	16/61 (26.2%)	16/63 (25.4%)	12/60 (20%)

^*Conversion definitions: (A) change from negative to positive ⩾0.35 IU/ml, (B) change from negative to positive ⩾0.35 IU/ml and 0.7 IU/ml absolute increase, (C) change from negative to positive ⩾1.0 IU/ml.

^**Reversion defnition: change form positive (⩾0.35 IU/ml) to negative (<0.35 IU/ml).