my mum experiense same problem for PR Application too, high ALT and GGT (Alt 50, GGT 65 ). Immigration NZ send back to check up again.
she decide not to eat any rice or flour product for 3 days , and green veg only for 2 week before medical check again. My mum was lucky to pass it 2 times, that is quite a significant dorp for GGT and ALT.