If liver screening is the same as a liver function test, it's a blood test which the Biochemistry Dept. do. There's a stack of things they look for to see which are within or outside of the normal range.
Most GPs that I know would regard raised Trigs and raised ALTs as typical of someone drinking too much alcohol. I had raised trigs for years and they always asked me and never believed me whan I said I didn't drink much at all. As soon as I cut down on sugar after diabetes, my trigs plumetted. Suagr is a cause of raised trigs, but the GPs didn't appear to be aware of that.
A liver scan however is different, but you'll have to wait ages for one of those. Mine took so long that they forgot about it and when my trigs came down, they said I didn't need it anymore.