bentiromide (PABA or Chymex) test
Indications
- test of pancreatic exocrine function
- according to ref 2, the bentiromide test is insensitive & no longer commercially available
Procedure
Bentiromide is administered orally with a test meal to stimulate pancreatic secretion. The bentiromide is hydrolyzed in the duodenum by chymotrypsin to release para-aminobenzoic acid (PABA). The PABA is absorbed in the intestine & metabolized to hippurate PABA glucuronide & PABA acetylate. These metabolites of PABA are secreted into the urine.
With pancreatic insufficiency, less bentiromide is hydrolyzed & less absorbed by the intestine & secreted in the urine. Thus the test is an indirect measure of duodenal chymotrypsin activity.
The test measures all arylamines in the urine which are normally insignificant compared with PABA arylamines following administration of bentiromide.
The optimal dose of bentiromide is about 500 mg. It is recommended the 1 liter of fluid be given as part of the test.
The test is affected by medications including antibiotics, analgesics, sulfonamides & diuretics. Prunes & cranberries contain hippurate resulting in false elevation of urinary arylamines. Test results are affected by intestinal absorption & renal insufficiency.
Radiolabeled PABA may be administered with bentiromide. Low recovery of radiolaled PABA indicates diminished intestinal absorption or renal excretion.
More general terms
Additional terms
- bentiromide; N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BTP)
- para-aminobenzoic acid; 4-aminobenzoic acid (PABA, Paraben, Potaba)