The poor man's isoamylase analysis (wheat inhibitor). Does it work?

The value of a wheat inhibitor assay to measure the pancreatic isoamylase fraction in the serum was evaluated in a clinical trial. Fifty-four patients with a variety of disorders and wide range in serum amylase levels were studied comparing pancreatic isoamylase levels measured by both cellulose acetate membrane electrophoresis and wheat inhibitor assay. The overall correlation was excellent (r = 0.96), and was best when the total serum amylase was high. The predominate serum isoamylase was correctly predicted in 45 of 54 (83%) patients, with an overall specificity of 73 per cent and sensitivity of 96 per cent. Because it is easy to perform, the test is recommended for clinical use by those without access to more sophisticated forms of isoamylase analysis.