Alt was 130 a month ago. recently retested and it's 34. is this something to worry about?

Many causes: ALT goes up for many causes. Since 130 is pretty high it would be good for you to get tested just to make sure you do not have hepatitis B and C. Avoiding alcohol and excessive tylenol (acetaminophen) would also be a good idea. It says that your US was abnormal and that would need follow up as wel.

Probably not.: you will probably never know why the ALT was elevated a month ago, but now that it is back to normal, it probably means that it is inconsequential. I would recheck it in 6 to 12 months to be sure that it remains normal. If it increases again, you should have a work up to determine why it was abnormal in the first place. Good luck.