A sulfur amino acid intermediate in methionine metabolism, raised by B12, folate or B6 deficiency and by polymorphisms such as MTHFR. It was proposed to promote endothelial dysfunction and thrombosis, and it is strongly and consistently associated with cardiovascular events across observational cohorts. It has since become the standard cautionary tale about exactly how much that kind of association is worth.
Lonn E, Yusuf S, Arnold MJ, et al. (HOPE-2) “Homocysteine Lowering with Folic Acid and B Vitamins in Vascular Disease.” N Engl J Med 2006;354:1567–1577 lowered homocysteine by roughly 25% in 5,522 high-risk patients using folic acid with B6 and B12, and did not reduce major cardiovascular events overall — a stroke reduction appeared, but not for MI or cardiovascular death. Later Mendelian randomisation data are similarly unsupportive of a direct causal cardiovascular role. The test remains clinically useful inside a B12 or folate deficiency workup.
Lonn E, et al. N Engl J Med. 2006. PubMed: PMID 16531613
Singapore guidance
Not one of the named screening tests
Not among the tests Singapore’s national screening committee names for cardiovascular risk screening.
Source: Screening Test Review Committee report 2026, Volume 1 (Academy of Medicine Singapore and Ministry of Health, February 2026). The full national list · How this is used.
What you would actually pay
- Healthier SG
- Not subsidised
- MediSave
- Not among the screenings named for outpatient claims
Source: Healthier SG Screening (HealthHub) and MediSave outpatient care (Ministry of Health). Absence from either list is not a statement that the test is discouraged — only that no subsidy or claim applies. Gross prices compared.
What it costs when it is wrong
- Basis
- No published harm criterion found
- Severity
- Not documented
No published harm criterion found for this test.
An empty finding, not a clean bill of health: this means nothing documented was found for this test. It is not a claim that the test is safe.
Screening harm is not only a laboratory question: the committee’s own criteria advise against a test when “the screening test, or follow-up tests arising from a positive screen, are associated with significant medical risks”. Sources on overdiagnosis → · How this is graded.
FAQ
Is the Homocysteine worth doing in Singapore?
The evidence behind Homocysteine is graded weak for screening an asymptomatic adult. It is most appropriate for suspected B-vitamin deficiency or unexplained thrombosis/neuropathy — not as a cardiovascular or longevity screen. It typically costs S$40–60 in Singapore. It is not routine; only within a B12/folate/neurological workup.
Weighing this against something else? Compare it with two other tests → · Price it inside a panel →