This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Which of the following is the best test for assessment of intestinal malabsorption? 
Select and explain. 
A. Fecal fat estimation, B. Serum lactose levels, C. Serum amylase levels, D. NBT-PABA test
A: Fecal fat estimation
Answer: A: Fecal fat estimation 
Explanation: Ans: A(Ref: Harrison 19/c p193(S)Fecal fat estimation - Gold standard test for diagnosis of malabsorption.Intestinal malabsorption diagnosis:D-xylose test.Tests for xylose absorption in intestinal villi.Distinguishs intestinal from pancreatic malabsorption.Pancreatic malabsorption diagnosis:NBT-PABA & serum amylase.