LABORATORY AND CLINICAL-EVALUATION OF ASSAYS FOR BETA-HYDROXYBUTYRATE

We have performed a two-part evaluation of assays for beta-hydroxybuty rate (beta HB). In Part I, we evaluated the analytical acceptability o f a dry film, self-contained analyzer for beta HB measurement (KetoSit e; GDS Diagnostics, Elkhart, Ind). The assay response is linear and be tween-day imprecision is acceptable. Acetoacetate (AcAc) interferes se verely with this assay. This interference could be minimized by diluti on of serum before the assay. With this predilution protocol, KetoSite beta HB results compare favorably with an automated Sigma (St. Louis, Mo) beta HB assay. In Part II, we compared the clinical utility of be ta HB measurements (Sigma) with the qualitative measurement of ketones using the nitroprusside test (Acetest; Bayer, Elkhart, Ind) for the d iagnosis and management of diabetic ketoacidosis (DKA). Test results f or both assays were abnormal for all patients with DKA on admission. H owever, frequent monitoring with either test during the management of uncomplicated DKA added little if any additional clinical information over routine measurements of serum glucose and total carbon dioxide.