Don't think a stomach emptying test would help. I had a stool test because I lost 18lbs. and was having 15-20 soft stools a day, yucky colors, white, yellow and sometimes orange rings (fat). Doctor said it was a sign that my pancreas enzymes level was low and my food was not being digested. I was becoming malnourished. So I had 5 stool specimens. The one for enzymes came back so low, and the one for Crohn's and Ulcerative Colitis came back abnormal. That is why I am on pancreatic enzymes now. They help digest food because I lack them. I am having a repeat stool test next week to see if they helped and to see if the Crohn's and UC improved.
Good luck...wish I could help more. Louise