Homocysteine
- Description
- One-step immunoassay using CMIA technology on Architect Due to the relocation of the Nutristasis service to the Blackfriars Hub site, this test is not currently accredited by UKAS to ISO15189
- Clinical details
- The loss of a single methyl group from dietary methionine facilitates numerous essential methylation reactions and produces homocysteine, a sulphur containing amino acid. Approximately 50% of homocysteine is re-methylated via a vitamin B12 dependent remethylation cycle in which a methyl group from 5-methyltetrahydrofolate, the main circulatory form of folate, is donated to homocysteine to reform methionine. An alternative route of homocysteine catabolism is via the transsulphuration pathway where homocysteine is condensed with serine to form cystathionine in a vitamin B6 dependent reaction. Nutritional deficiencies and/or inborn errors that affect either of these pathways can lead to hyperhomocysteinemia, characterised by raised plasma concentrations of total homocysteine (tHcy). Elevated total plasma homocysteine (tHcy) is considered to be a significant independent risk factor for various diseases including cardiovascular disease, Alzheimer's disease and cancer. In the majority of individuals, hyperhomocysteinemia can be successfully corrected through the introduction of nutritional supplements (e.g. folic acid- once a satisfactory vitamin B12 status has been confirmed or the inclusion of adequate dietary folic acid.
- Related condition
- Reference range
Cut-offs are age and sex related
- 0-1 yr <6.5 umol/L
- 2-15 yr <10umol/L
- 15-65 yr females <13 umol/L
- 15-65 yr males <15 umol/L
- >65 yr all sexes < 16 umol/L
Comment for pregnancy:
- In pregnancy-, trimester specific homocysteine reference cut-offs apply: First trimester <7 umol/L, Second trimester <7 umol/L, Third trimester <10 umol/L
- Units
- umol/L
- Synonyms
- tHcy/hyperhomocysteinemia, homocystinuria
- Testing site
- Synnovis : Reference Services : Blackfriars Hub
- Laboratory
- Nutristasis Unit
- Sample type and volume required
- SST, lithium heparin or potassium EDTA Minimum 1mL
- Call in advance
- No
- Special sample instructions
Specimens should be placed on ice following collection and plasma separated from red blood cells within two hours from blood collection. Delayed removal of red blood cells can result in artificially high concentrations of tHcy.
- Storage and transport
- Separated plasma/serum can be sent by first class post
- Turnaround time
- 10 days
- Contacts
Nutristasis Unit at Blackfriars Hub
Phone: 0204 591 0055
Email: Nutristasis@synnovis.co.uk
Nutristasis
Floor 1, Synnovis Hub
Friars Bridge Court
41-43 Blackfriars Road
London
SE1 8NZ