One of my favorite labs to run on clients is a GI-Map. This is such a comprehensive test that looks at parasites, bacteria, H.Pylori, yeast & fungi, candida, and many markers of intestinal health. 

This video explains all that can be found on the test and how it can correlate with gut issues like gas, bloating, diarrhea, and constipation as well as other symptoms like migraines, fatigue, brain fog, anxiety, and more.