I am a Doctor, 25 yrs old male, ALT 80, AST within Normal, also fluctuates, Did extensive evaluation for the last five years. All test are normal except ALT which fluctuates. Liver Enzymes are taken from sample of a population. Not all people will have a similar range of liver enzymes. Seen so many Gastroenterologists, hepatologists as they are my professors in the hospital. They told me the same thing, liver enzymes are of different ranges for some people. I worked for 2 years now, encountered many patients with high ALT and AST without any clinical significance. Rasticle, you are right about the variance of rangt
Usually the liver levels take a long time to return to normal. Thats why doctors usually order a retest several weeks or months after the first initial test.
45 is normally the high end of the reference range in labs. The thing about it is they get this reference range from a small subset of the population for statistics. My ALT is normally around +-90. I've been tested for everything and they have never found any structural or functional problems with my liver. I think it is not uncommon for people to outside of the normal reference range on liver enzymes.
But I'm not a doctor, this is just what I've learned from all my research and I have doctors in the family.