other investigations for small-bowel disease may include the breath test with carbon-14-labelled glycocholic acid , the lactose tolerance test , duodenal aspiration for giardiasis , analysis of serum immunoglobulins and , on occasion , isolation of vasoactive intestinal polypeptide hormone ( which may aid the diagnosis of functioning tumours of the pancreas or small bowel ) .
C0013303
duodenal
C0021852
small bowel