A B12 and folate test that looks at why a deficiency exists, not just that it does.
Referred by a GMC-registered GP, results reviewed by the same doctor
Taken at a partner site near you
Results explained in plain English, not just a number
Your NHS records in the room, with your consent
Care led personally by Dr Khan
Attentive, unhurried care that listens properly
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B12 and folate are both needed to make healthy red blood cells and to keep the nervous system working properly. Deficiency in either causes fatigue, poor concentration and low mood — symptoms vague enough to be attributed to almost anything else.
B12 deficiency matters more than its reputation suggests, because prolonged deficiency causes nerve damage that does not fully reverse. Finding it early is the entire point.
Vitamin B12 — the total level in the blood. Its main limitation is that most circulating B12 is bound to a protein that cannot deliver it to your cells, so the total can look adequate while the usable fraction is not.
Active B12 (holotranscobalamin) and methylmalonic acid can be added where the total is borderline. These distinguish genuine deficiency from a low-normal reading, and borderline results are common and frequently dismissed.
Folate — works alongside B12. The two must be interpreted together, and in a specific order: treating folate deficiency while B12 is still low can worsen neurological damage. B12 is always corrected first, and this is not a subtlety to leave to chance.
The wider panel includes iron, ferritin, vitamin D, zinc, magnesium and calcium, because these deficiencies cluster and produce indistinguishable symptoms. Testing them one at a time wastes months.
Intrinsic factor antibodies can be added to identify pernicious anaemia — the autoimmune cause, which means lifelong treatment rather than a course of supplements.
The single most useful piece of advice: get tested before you start supplementing. Over-the-counter B12 normalises the blood level within days while leaving the underlying cause — which may be pernicious anaemia — undiagnosed. If you have already started, tell us, because the result will be falsely reassuring.
Included: vitamin B12 · folate · vitamin D · iron · ferritin and full iron status · zinc · magnesium · calcium · albumin · total antioxidant status.
Active B12 and intrinsic factor antibodies can be added where pernicious anaemia is suspected — the latter is what distinguishes an autoimmune cause, which needs lifelong injections rather than tablets.
1. Consultation. Diet, medication and gut history all shape what the result will mean, and neurological symptoms change the urgency.
2. Referral. To a Randox Health clinic. We generally request the wider vitamin and mineral panel alongside full blood count and coeliac screening, since malabsorption is a common shared cause.
3. The sample. A single blood draw, no fasting. Tell the GP if you already take B12 supplements or have recently had injections — both make the result difficult to interpret and we would rather know beforehand than puzzle over it after.
4. Results review. A GP interprets B12 and folate together and in the right order, identifies whether the cause is dietary or absorptive, and arranges treatment where needed — including establishing whether it is lifelong.
No fasting required. Tell the GP if you already take B12 supplements or have recently had injections — both make the result difficult to interpret.
Most circulating B12 is bound to a protein that cannot deliver it to your cells. Only about 20% is on the carrier that can. So a total B12 can look adequate while the usable fraction is not.
Where the total is borderline, active B12 (holotranscobalamin) or methylmalonic acid settle it. Borderline results are common and are frequently waved through — and they are exactly the ones worth pursuing.
Treating folate deficiency while B12 is still low can worsen neurological damage. The blood picture improves while the nerve damage progresses silently.
B12 is always corrected first. This is not a subtlety to leave to chance, and it is why the two are read together rather than separately.
Neurological symptoms change everything. Pins and needles, numbness, unsteadiness or memory change in someone with a low-normal B12 warrant treating rather than watching — because the blood changes reverse completely and the nerve damage may not.
The longer it has been present, the less likely full recovery becomes. That asymmetry is the whole argument for acting early.
Raised mean cell volume on a full blood count points towards B12 or folate rather than iron — and where iron deficiency coexists, the two cancel out and the MCV can look entirely normal. That is one reason both are measured together.
Intrinsic factor antibodies are highly specific but not very sensitive — a negative result does not exclude pernicious anaemia. Where the clinical picture fits, treatment proceeds regardless of a negative antibody.
B12 will be high after injections, and that tells you nothing. Treatment is monitored on symptoms and the full blood count.
Any service selling you repeat B12 panels while you are having injections is selling tests.
B12 injections for confirmed deficiency are provided free on the NHS, and pernicious anaemia qualifies you for a medical exemption certificate in England — making all your NHS prescriptions free.
High-dose oral B12 is cheap and available over the counter, and where the cause is dietary it works perfectly well.
The diagnosis, not the injection. Interpreting a borderline result properly, testing intrinsic factor antibodies, and correcting folate, iron and B12 in the right order.
No — and this is the single most useful thing on the page.
Over-the-counter B12 normalises the blood level within days, so a test taken afterwards looks reassuring while the underlying cause — possibly pernicious anaemia, needing lifelong treatment — goes undiagnosed.
Test first. If you have already started, tell us.
Possibly, and borderline results are commonly dismissed when they should not be. Active B12 or methylmalonic acid distinguishes genuine deficiency from a low-normal reading — particularly where symptoms fit.
Because treating folate while B12 is still low can worsen neurological damage. The blood picture improves while the nerves deteriorate.
B12 always comes first.
Yes — long-term metformin reduces B12 absorption, and it is badly under-monitored. Anyone on it for years with fatigue, pins and needles or poor concentration should have their B12 checked.
The same applies to long-term omeprazole and similar acid-suppressing medicines.
The test for pernicious anaemia — the autoimmune cause, which means lifelong injections rather than a course of tablets.
A negative result does not exclude it, since the test is specific but not very sensitive. Where the picture fits, treatment proceeds regardless.
It depends entirely on the cause. Dietary deficiency responds well to high-dose oral B12, which is cheap and available over the counter.
Absorption failure — pernicious anaemia, or after stomach or bowel surgery — needs injections, because tablets cannot get in reliably.
Energy and mood often improve within weeks. Nerve symptoms take weeks to months, and damage present for a long time may not fully reverse.
Yes, considerably — and please say so. Nitrous oxide inactivates B12 and causes severe, sometimes irreversible nerve damage, and it is increasingly seen in younger people.
It changes both the urgency and the treatment, and we are not here to judge.
No — it will be high and it tells you nothing. Treatment is monitored on symptoms and the full blood count.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 23, 2026
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Your NHS record in the room
Written treatment plan
Told when a test isn’t needed
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Same day, usually
20 minutes
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Yes, and told why
£40 for 20 minutes
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Typically 10 minutes
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Usually
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Same day
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Same-day access is usually available, from 6am to 10pm, seven days a week. You choose a time that suits you rather than waiting on hold at 8am.
Yes. Care is led personally by Dr Mohammad Khan, so you are not passed between clinicians. Continuity is the point of a small practice: someone who knows your history and is listening attentively rather than working through a checklist.
Yes, with your consent. We can access your Summary Care Record during the consultation, so your current medications, allergies and significant history are in the room. That means fewer questions you have already answered elsewhere, and safer prescribing.
No. We are not here to replace GPs, only to support them. Your NHS practice remains responsible for your ongoing care, and with your consent we write to them after the consultation. We are useful when you need to be seen sooner, or want more time than a standard appointment allows.
Twenty unhurried minutes and a comprehensive assessment. A written treatment plan is included, along with any prescription, sick note or referral letter arising from the consultation, at no extra charge.
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It means the diagnosis can usually be made from your history and photographs, and that treatment can be arranged safely without examining you. Where a condition is not marked treatable online, it is because examination is the diagnosis — listening to a chest, feeling an abdomen, examining an ear or a joint — or because a procedure or device is needed.
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If your problem turns out to be genuinely outside what we can do remotely, the doctor will tell you straight away, point you to the right service, and refund your fee in full. We would rather do that than fill twenty minutes to justify the charge.
Call 999 or go to A&E — do not book an online appointment and do not wait for a reply to an email. For urgent problems that are not emergencies, NHS 111 is available 24 hours a day, online or by phone, and can direct you to the right service.
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