Objective: Select the appropriate test for malabsorption syndromes of different etiologies,

Steatorrhea due to pancreatic insufficiency: Bentiromide test (Bentiromide is broken down by pancreatic enzyme chymotrypsin to form PABA. PABA is excreted in urine. Low excretion signifies diagnosis. Treatment is replacement of enzymes orally.

Celiac Disease: Small bowel biopsy using Crosby's capsule (Shows flattening of villi but deepening of crypts). Treatment is Avoidance of Gluten (in wheat). Associated dermatitis herpetiformis is itchy and responds to Dapsone but before you give Dapsone, please check G6PD level as dapsone causes hemolysis in patients with G6PD deficiency.

Blind Loop syndrome (Bacterial overgrowth syndrome): C14 Xylose breath test (Bacteria break down Xylose which is then turned into CO2 that is exhaled). Breath test detects high levels of CO2 with C14. Treatment is with Broad spectrum antibiotics.

Giardiasis: Stool microscopy for ova and parasites or Giardiasis specific antigen in stool. Treatment is with (Flagyl) Metronidazole. 

Osmotic diarrhea due to concentrated feeds: Stool osmolality (Also by stopping feeds). Diluting the feed should help avoid diarrhea.