title: Improving the reliability of total and high-density lipoprotein cholesterol measurements. Four testing strategies compared in a high-risk population.
abstract: Four testing strategies for assessing total and high-density lipoprotein cholesterol are compared in a homogeneous group of male outpatients at increased risk for cardiovascular disease: (1) a single measurement at one occasion; (2) the mean of duplicate measurements at one occasion; (3) the mean of single measurements in specimens collected 1 week apart; and (4) the overall mean of duplicate measurements at two occasions 1 week apart. Results of strategy 1 were comparatively less reliable as demonstrated by lower intraclass correlation coefficients and higher within-subject variance components. Use of strategy 3 decreased within-subject variance by 50% and improved the 95% confidence interval by 30% for both total and high-density lipoprotein cholesterol, compared with strategy 1. Duplicate testing on either one or two occasions resulted in a nominal improvement in reliability and confidence. Calculating the mean of single measurements in specimens collected 1 week apart is clinically useful because: (1) it reduces the risk of misclassification, (2) it improves intervention monitoring, (3) it supports the National Cholesterol Education Program guidelines for total cholesterol, and (4) it improves the use of high-density lipoprotein as an independent risk factor.
authors.affiliation: Laboratory Service, Durham (NC) Veterans Affairs Medical Center.
authors.forename: R H
authors.initials: RH
authors.lastname: Christenson
authors.forename: J R
authors.initials: JR
authors.lastname: Roeback
authors.forename: T E
authors.initials: TE
authors.lastname: Watson
authors.forename: K M
authors.initials: KM
authors.lastname: Hla
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001774:Blood Chemical Analysis / Q000592:standards*; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D008076:Cholesterol, HDL; D002784:Cholesterol