We compared two enzymatic cholesterol methods with the standardized chemical method used in the Lipid Research Clinic's (LRC) program. The methods were used to measure total cholesterol and high density lipoprotein (HDL) cholesterol in heparin-MnCl2 supernatants of 1,812 sera collected over a 16-mth period from subjects who were sampled as part of the Hispanic Health and Nutrition Examination Survey. Thirty percent of the subjects had fasted for 12 h or more before venepuncture. The enzymatic total cholesterol values were 1.4-1.8% lower than the LRC method and both enzymatic methods correlated highly with the LRC method (r greater than 0.97). The enzymatic HDL cholesterol values were 2.4 and 6.4% higher than the LRC method, and the correlation between the enzymatic and LRC methods was greater than 0.93. The differences between the enzymatic and LRC methods were the same in samples from fasting and non-fasting subjects.