title: Short-term and long-term variability of plasma homocysteine measurement.
abstract: Within-person and methodological variability of a given analyte are important elements in determining whether an individual has altered concentrations of that analyte. We report the short-term (1 month) within-person, between-person, and methodological variability of plasma homocysteine in 20 healthy participants from whom samples were drawn weekly for 4 weeks. The short-term between-person variance was high, whereas within-person and methodological variances were relatively very low, giving a high reliability coefficient (R) for homocysteine (R = 0.94). The long-term (30 months) reliability coefficient was 0.65, but was greatly influenced by an outlier (R = 0.82 with the outlier excluded). The data suggest that an individual's plasma homocysteine concentration is relatively constant over at least 1 month, and a single measurement characterizes the average concentration reasonably well.
authors.affiliation: Department of Laboratory Medicine and Pathology, School of Medicine, University of Minnesota, Minneapolis 55455, USA. gargx002@maroon.tc.umn.edu
authors.forename: U C
authors.initials: UC
authors.lastname: Garg
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Zheng
authors.forename: A R
authors.initials: AR
authors.lastname: Folsom
authors.forename: Y S
authors.initials: YS
authors.lastname: Moyer
authors.forename: M Y
authors.initials: MY
authors.lastname: Tsai
authors.forename: P
authors.initials: P
authors.lastname: McGovern
authors.forename: J H
authors.initials: JH
authors.lastname: Eckfeldt
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood; D000704:Analysis of Variance; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012727:Sex Characteristics
chemical_list: D006710:Homocysteine