Short-term variability in the measurement of plasma homocysteine, fasting and post-methionine loading.
OBJECTIVE
Hyperhomocysteinemia is associated with premature cerebral, peripheral and coronary vascular disease. Evaluation of the significance of changes in plasma total homocysteine (tHcy) results obtained by analysis of serial specimens may be accomplished only by taking into account biologic (between-person and within-person) as well as analytical variation. Since the repeatability of a measurement significantly determines our ability to associate tHcy level with the presence of disease, this study was performed to evaluate various components of variation in tHcy values.


METHODS
We report the within-person, between-person, and methodological variability of tHcy, both fasting and postmethionine load (PML) values, in 20 healthy volunteers from whom samples were drawn weekly for 4 weeks.


RESULTS
The short-term reliability coefficient (R) was 0.72 for fasting tHcy and 0.83 for PML tHcy.


CONCLUSIONS
The current study demonstrates for the first time that the short-term reliability coefficient for PML tHcy is relatively high (0.83), suggesting that an individual's PML tHcy, like fasting tHcy, is relatively constant over at least one month, and that a single measurement should provide a reasonable characterization of an individual's PML tHcy concentration.
Tsai
M Y
MY
Department of Laboratory Medicine and Pathology, University of Minnesota, Medical School, 420 Delaware St., SE, Box 609, Minneapolis, MN, USA. tsaix001@tc.umn.edu
McGovern
P
P
Kennedy
E L
EL
Hanson
N Q
NQ
D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D005215:Fasting; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism*; D008875:Middle Aged; D015233:Models, Statistical; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors
D006710:Homocysteine; D008715:Methionine