Low diagnostic value of fasting and post-methionine load homocysteine tests. A study in Dutch subjects with homocysteine test indications.
BACKGROUND
Homocysteine is a cardiovascular disease risk factor. We investigated, both in subjects with past plasma total homocysteine (tHcy) test indications and healthy adults, the diagnostic value of a fasting (tHcy) (f-tHcy) and the added value of a post-methionine-load tHcy (postload-tHcy).


METHODS
Plasma homocysteine cut-off values were retrospectively used for hyperhomocysteinemia assessment in 3477 subjects with past tHcy test indications and 177 apparently healthy subjects. Cut-off values were based on reference limits (f-tHcy < or = 15.0; postload-tHcy < or = 50.0 micro mol/l), relative risk (f-tHcy < or = 12.0, postload-tHcy < or = 38.0; or f-tHcy < or = 10.0 micro mol/l) and vitamin-optimized reference limits (f-tHcy < or = 9.3; postload-tHcy < or = 35.1 micro mol/l).


RESULTS
Use of the American Heart Association 10 micro mol/l f-tHcy cut-off value gave hyperhomocysteinemia prevalences of 65% in subjects with past tHcy test indications and 50% in healthy subjects. The combination of the vitamin-optimized reference limits for f-tHcy and postload-tHcy gave a hyperhomocysteinemia prevalence of 79% in subjects with tHcy test indications, of which only 5% was on account of increased postload-tHcy. Corresponding values for healthy subjects were 68% and 3%, respectively.


CONCLUSIONS
Employment of a 10 micro mol/l (American Heart Association) or 9.3 micro mol/l (vitamin-optimized reference) cut-off value leaves no indications for tHcy testing from an evidence-based point-of-view.
Fokkema
M R
MR
Department of Pathology and Laboratory Medicine, University Hospital Groningen, CMC-V, Room Y1.165, P.O. Box 30.001, NL-9700 RB, Groningen, The Netherlands
Dijck-Brouwer
D A J
DA
van Doormaal
J J
JJ
Reijngoud
D J
DJ
Muskiet
F A J
FA
D000328:Adult; D002318:Cardiovascular Diseases / Q000097:blood*; D005215:Fasting / Q000097:blood*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D008297:Male; D008715:Methionine / Q000008:administration & dosage*; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D012016:Reference Values; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity
D006710:Homocysteine; D008715:Methionine