MD Dopers: How is ALT reference range calculated?

I just had some blood work done and everything is fine, but I’m looking at my lab results and looking up things I don’t know. It seems ALT doesn’t have a standard reference range but rather it is calculated by the lab. Mine is 30-65 U/L. How is this calculated in the lab? Is it more due to the type of testing agent/equipment or more due to my age, gender, and such?


Alanine transaminase? Usual reference range is 8-40. If your doctor isn’t concerned about the result though, you have nothing to be concerned about. All the seriously ill people I’ve seen, with regards to liver disease, have trememndously higher results above the reference range.

It is not uncommon for a lab to create it’s own reference ranges depending on the local healthy population. So the reference range is just calculated using the normal range for healthy men and women.

The result isn’t so much calculated, as it is tested for. It is an enzyme that we have plenty of methods to measure using chemistry tests.