(Biochemistry) |
Investigation | : | Homocysteine | ||||||||||
Specimen type | : | Plasma | ||||||||||
Spec container | : | Fluoride (K EDTA) | ||||||||||
Volume required | : | 4 ml | ||||||||||
Reference range | : | see below µmol/l | ||||||||||
Turnaround | : | <10 days | ||||||||||
Potassium EDTA specimens are also acceptable.
Reference range: | Normal: | <15µmol/L |
Moderate hyperhomocysteinaemia: | 16-30µmol/L | |
Intermediate hyperhomocysteinaemia: | 31-100µmol/L | |
Severe hyperhomocysteinaemia: | >100µmol/L |
Delayed sample separation can artificially increase homocysteine levels. Samples must be transported to the laboratory immediately and centrifuged within 1 hour. | |
Homocystinuria, methylenetetrahydrofolate reductase (MTHFR) mutation 677C->T. | Down's Syndrome |
Smoking | Vitamin intake (folate, cobalamin, B6, B12), exercise. |
Folate deficiency, cobalamin deficiency, renal failure, hypothyroidism, cardiovascular disease, cerebral vascular accident, thrombophilia | |
Anti-folates (methotrexate, anticonvulsants, trimethaprim), nitrous oxide anesthesia, L-Dopa, fibrates, cyclosporin. | |
Pregnancy |
Other investigations to consider when plasma homocysteine levels are raised:
# Used to reveal additional abnormalities of the homocysteine metabolism
not detected by homocysteine concentration measurements. An elevated homocysteine level post methionine load must be taken into account in the general identification of patients bearing trans-sulphuration defects (e.g. vitamin B6 deficiency) or heterozygotes for cystathionine β-synthase (CBS) deficiency. Please contact duty biochemist for further information.
Additional information on Homocysteine and its clinical use can be found here:
Homocysteine.