There is no single, specific test for malabsorption. As for most<unk>  conditions, investigation is guided by symptoms and signs. A range of different conditions can produce malabsorption and it is necessary to look for each of these specifically. Many tests have been advocated, and some, such as tests for pancreatic function are complex, vary between centers and have not been widely adopted. However, better tests have become available with greater ease of use, better sensitivity and specificity for the causative conditions. Tests are also needed to detect the systemic effects of deficiency of the malabsorbed nutrients (such as anaemia with vitamin B12 malabsorption). Classification Some prefer to classify malabsorption clinically into three basic categories: # selective, as seen in lactose malabsorption. # partial, as observed in abetalipoproteinaemia. # total, as in exceptional cases of coeliac disease. Blood tests * Routine blood tests may reveal anaemia, high CRP or low albumin; which shows a high correlation for the presence of an organic disease. In this setting, microcytic anaemia usually implies iron deficiency and macrocytosis can be caused by impaired folic acid or B12 absorption or both. Low cholesterol or triglyceride may give a clue toward fat malabsorption. Low calcium and phosphate may give a clue toward osteomalacia from low vitamin D. * Specific vitamins like vitamin D or micronutrient like zinc levels can be checked. Fat soluble vitamins (A, D, E and K) are affected in fat malabsorption. Prolonged prothrombin time can be caused by vitamin K deficiency. * Serological studies. Specific tests are carried out to determine the underlying cause. :IgA Anti-transglutaminase antibodies or IgA Anti-endomysial antibodies for Coeliac disease (gluten sensitive enteropathy). Stool studies * Microscopy is particularly useful in diarrhoea, may show protozoa like Giardia, ova, cyst and other infective agents. * Fecal fat study to diagnose steatorrhoea is rarely performed nowadays. * Low fecal pancreatic elastase is indicative of pancreatic insufficiency. Chymotrypsin and pancreolauryl can be assessed as well Radiological studies * Barium follow through is useful in delineating small intestinal anatomy. Barium enema may be undertaken to see colonic or ileal lesions. * CT abdomen is useful in ruling out structural abnormality, done in pancreatic protocol when visualising pancreas. * Magnetic resonance cholangiopancreatography (MRCP) to complement or as an alternative to ERCP. Interventional studies Biopsy of small bowel showing coeliac disease manifested by blunting of villi, crypt hyperplasia, and lymphocyte infiltration of crypts. * OGD to detect duodenal pathology and obtain D2 biopsy (for coeliac disease, tropical sprue, Whipple's disease, abetalipoproteinaemia etc.) * Enteroscopy for enteropathy and jejunal aspirate and culture for bacterial overgrowth * Capsule Endoscopy is able to visualise the whole small intestine and is occasionally useful. * Colonoscopy is necessary in colonic and ileal disease. * ERCP will show pancreatic and biliary structural abnormalities. Other investigations * 75SeHCAT test to diagnose bile acid malabsorption in ileal disease or primary bile acid diarrhea. * Glucose hydrogen breath test for bacterial overgrowth * Lactose hydrogen breath test for lactose intolerance * Sugar probes or 51Cr-EDTA to determine intestinal permeability. Obsolete tests no longer used clinically * D-xylose absorption test for mucosal disease or bacterial overgrowth. Normal in pancreatic insufficiency. * Bile salt breath test (14C-glycocholate) to determine bile salt malabsorption. * Schilling test to establish cause of B12 deficiency.
medical cause of Malnutrition
medical cause of Malabsorption
medical cause of Gigantism
medical cause of Exocrine pancreatic insufficiency
complications of Malabsorption
medical cause of Constipation
medical cause of Abdominal pain
medical cause of Hives