Homocysteine is a measured amino acid that rises when folate, B12 or B6 status is low, when kidney clearance falls, and with some medicines and lifestyle factors. Practitioners use it to test whether a borderline B12 or folate result is a real shortfall, and to track the response to nutrition changes. Lowering it with B vitamins has not been shown to prevent heart attacks.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | Homocysteine only |
| Sample and collection | Blood draw at a collection centre |
| Preparation | Fast for 8 to 12 hours, water allowed. |
| Turnaround | Usually within a week |
| Available through | General Biochemistry. Available as a single test: Homocysteine Test. |
| Pricing | Price on sign-up |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What is the homocysteine reference range?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Adults | 5 to 15 µmol/L | Not set yet |
Labs set their own reference intervals and some use a lower upper limit, so read the result against the client's report. Mildly raised is commonly taken as 15 to 30 µmol/L, moderately raised 30 to 100 µmol/L, and severely raised above 100 µmol/L. Vively does not publish an optimal range for homocysteine yet.
Check a client's homocysteine result
Enter the value from your client's lab report to see where it sits against the typical lab range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange homocysteine testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and add the Homocysteine Test, or build your own panel. Add-on pricing shows when you sign up.
- Client collects. Your client collects at a partner collection centre, fasting, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
How can you order homocysteine?
Log in to the practitioner platform to add it to a client panel, or build and save your own from 100+ tests and panels.
- Log in to add this testHomocysteine Test1 marker · Heart & metabolicPrice on sign-up
How should homocysteine be used?
Use homocysteine to confirm a B12 or folate shortfall and to find causes you can correct, not as a stand-alone heart risk target.
The Master List currently holds 8 to 10 µmol/L. Because low homocysteine is not a clinical concern, a lower bound would flag healthy low results, so we show the lab range only until the Medical Director confirms the target. The RCPA Manual notes that below 10 µmol/L fasting is desirable in established vascular disease.
Homocysteine rises when cells lack folate or B12, so it helps decide whether a borderline serum B12 or folate is clinically relevant. Labs add it as a reflex test for this reason when B12 is inconclusive.
B vitamin trials lowered homocysteine but did not reduce myocardial infarction; the Cochrane review (Martí-Carvajal, 2017) found a small reduction in stroke, about 10%. Use it to find and correct a cause, and manage vascular risk through ApoB, blood pressure, glucose and smoking.
What should homocysteine be read with?
- HighHigh homocysteine with low or borderline B12
A functional B12 shortfall is likely. Consider active B12 and review diet, metformin, acid suppression and absorption.
- HighHigh homocysteine with low red cell folate
Folate shortfall. Check B12 before high-dose folic acid, which can mask B12 deficiency anaemia.
- HighHigh homocysteine with high MCV
Points towards B12 or folate deficiency. Refer for GP review.
- HighHigh homocysteine with low eGFR
Reduced renal clearance raises homocysteine; nutrition changes may move it less.
- HighHigh homocysteine with high TSH
Hypothyroidism raises homocysteine; recheck once thyroid function is addressed.
What can affect a homocysteine result?
- A recent high-protein meal raises it for several hours; collect fasting.
- Delayed separation of the sample raises it, so prompt processing matters.
- B12, folic acid and B6 supplements lower it.
- Reduced kidney function, hypothyroidism, smoking, heavy alcohol and high coffee intake raise it.
- Methotrexate, some anticonvulsants, levodopa, metformin (via B12) and nitrous oxide raise it.
- Pregnancy lowers it.
When should you refer the client to their GP?
- Homocysteine above 30 µmol/L: refer to the client's GP for assessment of the cause.
- Above 100 µmol/L: prompt medical review, as inherited disorders such as homocystinuria are possible.
- Any raised result with neurological symptoms (numbness, tingling, balance or memory change): GP review for B12 deficiency.
- Any raised result with low eGFR, a history of venous thrombosis, or premature cardiovascular disease in the family.
How should a client prepare for a homocysteine test?
Copy or print this to send to your client.
Preparing for your homocysteine test
- Fast for 8 to 12 hours before a morning collection. Water is fine.
- Avoid a large high-protein meal the evening before.
- Keep taking prescribed medicines and supplements unless your doctor tells you otherwise, and tell your practitioner what you take.
- Avoid testing while you have an acute illness. Book for once you have recovered.
- Take your pathology request to any of 3,700+ collection centres. Bring it printed or on your phone.
- Results usually come back within a week and go to your practitioner.
How do practitioners use homocysteine with clients?
Treat homocysteine as a cause-finder. Pair it with B12, red cell folate, MCV, eGFR and TSH, correct the shortfall you find, then retest after 8 to 12 weeks to confirm the response.
Homocysteine FAQs
Can a naturopath, nutritionist or dietitian order homocysteine through Vively?
Yes. Add the Homocysteine Test to any client panel on the Vively practitioner platform. Add-on pricing shows when you sign up. No account yet? Request free access.
When should homocysteine be retested?
About 8 to 12 weeks after a diet change or supplement starts, which is long enough for levels to settle. If the first result was in range and nothing has changed, there is little value in repeating it routinely.
Does a high homocysteine mean the client needs an MTHFR test?
Usually not. The homocysteine result already shows whether the folate pathway is coping, and management is the same either way: adequate folate and B12. The RCPA and RACGP advise against routine MTHFR testing, including for thrombophilia, and it has no Medicare rebate.
Should B vitamins be used to lower homocysteine for heart protection?
Not on their own. Trials lowered homocysteine with folic acid, B6 and B12 but did not reduce myocardial infarction, with a small reduction in stroke. Use supplements to correct a documented shortfall, and manage vascular risk through ApoB, blood pressure, glucose and smoking.
Why can homocysteine be high when serum B12 looks normal?
Serum B12 includes B12 bound to a carrier the cells cannot use, so it can look adequate while cells are short. Homocysteine rises when cellular B12 or folate is low, which is why labs add it when B12 is borderline. Active B12 helps clarify the picture.
References
- RCPA Manual. Homocysteine.
- Pathology Tests Explained. Homocysteine.
- Martí-Carvajal AJ, Solà I, Lathyris D, Dayer M. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database of Systematic Reviews. 2017.
- RACGP. First do no harm: MTHFR gene testing.
- Medicare Benefits Schedule. Items 66839 and 66842 (vitamin B12 testing, including homocysteine).