This is a completely normal TSH and suggests you have normal thyroid function on the current dose of levothyroxine -- not sure why you would stop the medicine - suggest discussing with your doctor first. 3rd generation means a very sensitive test.
3rd Generation test is a more sensitive TSH test which shows lower more sensitive readings. The reason for the sensitive tests are because it's important to know if TSH is being secreted at all.
I am not 100% sure but I think, TSH w/reflex to F/T4 means if a TSH results are less than or greater than your Labs TSH range, they want a Free T4 done in addition to the TSH.
As far as "OR = 20 years" probably a misinterpretation.
The > or = to 20 years means the reference range is for adults 20 years and older. Some labs report seperate reference ranges for kids.
Thanks for the information. I guess that everythings ok and I don't need to have any problems with my thyroid, and the syptoms I have probably not related. Saw family doctor today thought I had food poisoning but he thinks its my gall blader. I guess I could cancel the appt with the endo dr.