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Homocysteine (HCY) Assay
Hyperhomocysteinemia is a medical condition characterized by elevated levels of the intermediate amino acid, homocysteine (HCY), in the blood.1 HCY plays a key role in the remethylation/transmethylation and transsulfuration pathways that require folate, cobalamin, and pyridoxine as cofactors. Hence, any genetic defect in the enzymes that mediate HCY metabolism or deficiency of the cofactors can lead to the blood disorder.
Determinants and Factors Associated with Hyperhomocysteinemia
| Genetic Defects | Disease | Drugs | Lifestyle Factors |
|---|---|---|---|
| MTHFR-polymorphism (frequent) | B-vitamin deficiency (folate, B12, B6, B2) |
Anti-epileptics | Low exercise |
| CBS-deficiency (rare) | Impaired renal function | Methotrexate | Smoking |
| Malabsorption/chronic inflammatory bowel disease |
Omeprazole | High alcohol consumption | |
| Diabetes | Theophylline | High coffee consumption | |
| Hypothyroidism | Metformin | Poor nutrition |
Clinical Applications
An elevated HCY level is considered to be an independent risk factor for:
- Cardiovascular diseases (CVD)
- Atherosclerosis and thrombosis
- Stroke
- Peripheral vascular disease
- Dementia-type disorders
- Osteoporosis-associated fractures2,3,4,5,6,7
Reduction in HCY levels by 3 μmol/L from the existing levels lowers the risk of:
- Ischemic heart disease by 16%
- Deep venous thrombosis by 25%
- Stroke by 24%
Interpretation of HCY Levels2
In the general population, the normal levels of HCY range between 5 and 12 μmol/L.
| <10 µmol/L : favorable No need to treat (target level of intervention) |
10-12 µmol/L : tolerable Need to treat symptomatic patients |
12-13 µmol/L : moderate increase >30 µmol/L : severe increase Intervention required for all (apparently healthy individuals and patients) |
Management of Hyperhomocysteinemia2
- The HCY assay in combination with the clinical picture and underlying disease helps in determining the decision for treatment.
- In mild-to-moderate hyperhomocysteinemia, HCY levels can be reduced by folate and vitamin B6 and B12 supplementation.
Recommendations Based on HCY Levels
Reliable Answers to Critical Cardiac Questions
As a recognized leader in CVD testing, Siemens Healthcare Diagnostics offers multiple instrument choices for homocysteine testing, which allows for earlier identification of high-risk populations for cardiovascular diseases, facilitating initiation of quicker preventive and therapeutic measures.
Learn more.
Homocysteine assays are available on the following systems from Siemens Healthcare Diagnostics:
Click here to learn more about our complete menu of cardiac biomarkers.
References:
1. Wald DS, et al. Br Med J. 2002;325:1202-8.
http://www.ncbi.nlm.nih.gov/pubmed/12446535/.
2. Macy PA. Clin Lab Sci. 2001;14:272-5.
http://www.ncbi.nlm.nih.gov/pubmed/11760827.
3. Stanger O, et al. Clin Chem Lab Med. 2003;41:1392-403.
http://www.ncbi.nlm.nih.gov/pubmed/14656016.
4. Stanger O, et al. Z Kardiol. 2004;93(6):439-53.
http://www.ncbi.nlm.nih.gov/pubmed/15252738/.
5. Maron BA, et al. Annu Rev Med. 2008. [Epub ahead of print].
http://www.ncbi.nlm.nih.gov/pubmed/18729731.
6. American Heart Association. What is Homocysteine?
http://www.americanheart.org/presenter.jhtml?identifier=535. Dec. 2008.
7. van Meurs JB, et al. N Engl J Med. 2004;350:2033-41.
http://www.ncbi.nlm.nih.gov/pubmed/15141041.
8. American Heart Association. Homocysteine, Folic Acid and Cardiovascular Disease.
http://www.americanheart.org/presenter.jhtml?identifier=4677. Dec. 2008.
