A screening test for detecting sulfonylureas in plasma.

Hypoglycemia induced by surreptitious sulfonylurea ingestion can be difficult to distinguish from an insulin-secreting tumor. We describe a technique for detecting most of the common sulfonylurea drugs in plasma. After preliminary acidification, and extraction in ether, the residue is reconstituted and injected onto a Versapack high-performance liquid chromatography column. Detection is at 230 nm. This procedure gives good separation of chlorpropamide, glibenclamide, gliclazide, glipizide, and tolbutamide. Results are semiquantitative but the sensitivity of the assay is sufficient to detect and identify clinically active concentrations of all five drugs. It is a rapid and reliable screening test. Four representative case histories are reported in which the screen proved to be of diagnostic value.