We evaluated the quantification of high-density lipoprotein (HDL) cholesterol in plasma with the Boehringer Mannheim Reflotron reflectance photometric analyzer. The Reflotron is designed for testing in small to medium-size laboratories and physicians' offices. This HDL method does not require a manual precipitation step because the reagent tab contains dextran sulfate (Mr 50,000) and magnesium acetate. It takes 90 s to complete an analysis of 30 microL of plasma. Within-day standard deviations (SDs) were 0.02-0.04 mmol/L (6-16 mg/L). Total SDs over a three-month period were 0.03-0.06 mmol/L (11-23 mg/L). The Reflotron values averaged 0.02 mmol/L (6 mg/L) or 1.3% lower than the Hitachi 737 values; the standard error of the estimate (Sy.x) was 0.07 mmol/L (29 mg/L).