C A Finney | PubMed Health

PubMed1995

The effect of fasting status on the determination of low-density and high-density lipoprotein cholesterol.

PURPOSE: To determine the effect of a self-selected meal on concentrations of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in a screening setting and to determine the effect of using nonfasting values to classify individuals according to National Cholesterol Education Program guidelines. SUBJECTS AND METHODS: Study subjects were 115 employees who had previously participated in worksite total cholesterol screening, selected by stratified random sampling for sex and total cholesterol levels. Total cholesterol, triglycerides, HDL-C, and estimated LDL-C were determined before subjects ate a self-selected breakfast and 3 and 5 hours after eating it. RESULTS: LDL-C values determined 3 and 5 hours following breakfast were 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 (> or = 3.36 mmol/L) resulted in false-negative rates of 20% and 14%, respectively. Three- and 5-hour HDL-C values were approximately 4% and 1.5% lower, respectively, than fasting levels. Use of 3-hour HDL-C values to classify individuals with low fasting levels (< 0.91 mmol/L) resulted in no false-negatives, whereas 1 of 7 individuals with low fasting HDL-C was misclassified when 5-hour values were used. CONCLUSIONS: These results support the 1993 National Cholesterol Education Program guidelines that LDL-C levels should be determined only in fasting persons, and that nonfasting HDL-C values may be acceptable for screening purposes.

Adult↗

PubMed1991

Lipoprotein-cholesterol analysis during screening: accuracy and reliability.

OBJECTIVE: To evaluate the accuracy and reliability of lipoprotein-cholesterol measurements obtained during screening. DESIGN: Cross-sectional study. PARTICIPANTS: From November 1989 to January 1990, 154 adults were screened. MEASUREMENTS: Split venous samples from fasting participants were analyzed for total cholesterol, triglyceride, and high-density-lipoprotein (HDL) cholesterol with screening and standardized laboratory methods. Low-density-lipoprotein (LDL)-cholesterol levels were calculated using the Friedewald equation. Split venous samples from nonfasting participants were analyzed for total cholesterol. Capillary blood samples were analyzed for total cholesterol with the screening method. MAIN RESULTS: Total cholesterol measurements in screening venous blood samples were 5.4% and 3.8% lower than the laboratory values in samples from fasting and nonfasting participants, respectively. Triglyceride and HDL-cholesterol values in venous samples obtained from fasting participants were, on average, 9.8% and 11.2% lower than the respective laboratory measurements. Screening HDL-cholesterol values varied, differing from the laboratory values by as much as 40% in 95% of participants. In fasting participants, total cholesterol in capillary samples averaged 5.5% higher than in venous samples; in nonfasting participants the capillary samples were 3.1% higher. Screening for either total cholesterol or LDL cholesterol identified 93% of the persons with LDL-cholesterol values of 3.36 mmol/L (130 mg/dL) or higher. CONCLUSIONS: Total cholesterol can be reliably measured in samples from fasting or nonfasting persons. The values in capillary blood samples were slightly higher than those in venous samples. Screening HDL-cholesterol values were too variable to establish the HDL-cholesterol level reliably. Participants with high LDL-cholesterol levels were identified as accurately by measuring total cholesterol only when compared with calculating the LDL-cholesterol level from total cholesterol, triglyceride, and HDL-cholesterol concentrations.

Adult↗