Most primary care physicians are grossly under educated when it comes to HE. Your GI or Hepatologist will probly diagnose you.
If you have cirrhosis, you should discuss any feeling of being foggy headed, confused or if you have trouble completing thoughts or sentances.
Your doctor will probably order an ammonia blood test. Some people are highly sensitive to the ammonia level in their blood and show signs and symptoms even when their ammonia levels are normal. Others like myself can tolerate higher levels of ammonia without showing signs.