THE EFFECT OF FASTING STATUS ON THE DETERMINATION OF LOW-DENSITY AND HIGH-DENSITY-LIPOPROTEIN CHOLESTERS

PURPOSE: To determine the effect of a self-selected meal on concentrat ions of low-density lipoprotein cholesterol (LDL-C) and high-density l ipoprotein cholesterol (HDL-C) in a screening setting and to determine the effect of using nonfasting values to classify individuals accordi ng to National Cholesterol Education Program guidelines. SUBJECTS AND METHODS: Study subjects were 115 employees who had previously particip ated in worksite total cholesterol screening, selected by stratified r andom sampling for sex and total cholesterol levels. Total cholesterol , triglycerides, HDL-C, and estimated LDL-C were determined before sub jects ate a self-selected breakfast and 3 and 5 hours after eating it. RESULTS: LDL-C values determined 3 and 5 hours following breakfast we re approximately 7% and 2.5% lower, respectively, than fasting values. Use of 3-hour and 5-hour LDL-C determinations to classify individuals with elevated fasting levels (greater than or equal to 3.36 mmol/L) r esulted in false-negative rates of 20% and 14%, respectively. Three- a nd 5-hour HDL-C values were approximately 4% and 1.5% lower, respectiv ely, than fasting levels. Use of 3-hour HDL-C values to classify indiv iduals with low fasting levels (< 0.91 mmol/L) resulted in no false-ne gatives, whereas 1 of 7 individuals with low fasting HDL-C was misclas sified when 5-hour values were used. CONCLUSIONS: These results suppor t the 1993 National Cholesterol Education Program guidelines that LDL- C levels should be determined only in fasting persons, and that nonfas ting HDL-C values may be acceptable for screening purposes.