3rd Liver panel

I posted a while back stating my liver problem with not being diagnosed with hepatitis.

I've taken numerous conventional test and all have returned with negative results.  This is very frustrating not being able to pin point what is going on.  I've taken Anti-hepc, Surface antigen for B, and an IGM.

My first test was a liver panel:
Alkaline Phosphatase was 171 (should be less than 150)
ALT was 65 (should be less than 40)

My second test 3 weeks later on liver panel:
Alkaline Phosphatase was 152 (went down)
ALT was 83 (went up)

My Third test( which I got back yesterday, 3 months after the last ):
Alkaline Phosphatase was 146 (went back in range)
ALT was 46 (went down but still 6 over)

From my understanding from you guys is that low levels usually pertain to hepatitis C, which so far has been negative on my test.  Hepatitis B would be producing these results would they?  I'm very happy that my levels are down, but I know that doesn't mean anything.  The doctor has scheduled me for another test in 3 months to see where it is at.  My other question is, if my ALT level still stays over the limit, should I consider getting a biopsy to try and resolve what is going on?  I'm not a big drinker, but when I do drink alcohol, it gives me diarrhea, which is what prompted me to go to the doctor in the first place.