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Identify B12 or folate deficiency driving your fatigue, brain fog, or neurological symptoms with a simple home fingerstick kit.
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Check your vitamin B12 and folate levels with a simple home fingerstick test. Ideal for vegans, those on metformin.
Vitamin B12 and folate work in tandem to support red blood cell production, DNA synthesis, and neurological function. Deficiency in either nutrient can cause megaloblastic anaemia — a condition in which red blood cells become abnormally large and dysfunctional — as well as fatigue, peripheral tingling, memory problems, and low mood. B12 deficiency is particularly insidious because the liver can store enough to delay symptoms for years, even as reserves quietly deplete. It is most common in vegans and vegetarians, those taking metformin or proton pump inhibitors, and people with pernicious anaemia or other absorption disorders. Folate deficiency, by contrast, tends to develop faster and is common during pregnancy planning and in individuals with high alcohol consumption. This two-marker test is a straightforward starting point for investigating these overlapping conditions. Results are reviewed by a GMC-registered physician before being released to your secure dashboard.
Understand what each marker measures, why it matters, and what the science says — not just a list of numbers.
This panel is designed for adults who want a comprehensive, evidence-based picture of their metabolic health — not a GP referral panel.
Vegans and vegetarians relying on supplementation for B12
People taking metformin for type 2 diabetes or prediabetes
Anyone with fatigue, tingling extremities, or persistent brain fog
Women planning a pregnancy who want to confirm adequate folate status
Older adults with reduced intrinsic factor production
Serum B12 measures total circulating cobalamin, which includes biologically inactive analogues bound to haptocorrin. A result within the reference range therefore does not entirely exclude functional B12 deficiency; holotranscobalamin (active B12) and methylmalonic acid are more sensitive markers for tissue-level depletion but require additional testing. Serum folate reflects very recent dietary intake and can rise transiently after a single meal rich in leafy vegetables. A single normal folate reading does not rule out longer-term insufficiency; red cell folate is a more stable indicator of tissue stores but is not included here. This test does not diagnose pernicious anaemia, which requires intrinsic factor antibody and gastric parietal cell antibody testing.
From order to physician-reviewed report in as little as three working days.
Home fingerstick kit or mobile phlebotomist — choose at checkout.
Ideally fasting; detailed instructions included.
Pre-paid Royal Mail envelope included.
Secure online report with physician commentary in 3 to 5 working days.
Three options designed to fit your schedule, location, and preference — all producing a laboratory-standard sample.
Adults 18+ in mainland UK. Not suitable if you have had a transfusion in the last 3 months.
Order anytime; kit dispatched within 24 hours Mon–Fri.
Allow 24–48 hours for sample transit on top of lab processing time.
Adults 18+ within 20 miles of a serviced city centre.
Mon–Sun, 06:00–20:00. Next-day booking typical.
Sample reaches the lab within 24 hours of collection.
Adults 16+ with photo ID. Paediatric draws by appointment at selected sites.
Mon–Fri, with Saturday hours at most metropolitan locations.
Samples processed same-day at the receiving clinic.
Every test is processed in a UKAS ISO 15189-accredited laboratory, overseen by GMC-registered physicians, and governed by UK GDPR. No overseas processing, no offshore data.
Follow these guidelines to ensure accurate, reproducible results. Most markers are sensitive to recent food, exercise, and sleep.
Can't find your answer? Our clinical support team is available Monday to Friday, 9am–5pm.
Contact supportThe liver stores several years’ worth of vitamin B12, which is why deficiency can take two to five years to become symptomatic even after completely eliminating dietary sources. This is both a protective mechanism and a diagnostic challenge. By the time symptoms appear, neurological damage may already have begun in some cases. Regular monitoring is particularly important for vegans and for people who have had gastric bypass surgery or are taking medications that impair absorption.
Metformin, the most commonly prescribed medication for type 2 diabetes, is well documented to reduce B12 absorption from the gut, and guidelines now recommend B12 monitoring for anyone on long-term metformin therapy. Proton pump inhibitors (omeprazole, lansoprazole, pantoprazole) can also reduce B12 absorption by lowering gastric acid, which is needed to release B12 from food proteins. Methotrexate is a folate antagonist used in rheumatoid arthritis and cancer treatment and frequently causes folate depletion. Long-term anticonvulsants such as phenytoin can also lower folate.
Not entirely. Total serum B12 includes both active and inactive forms. Approximately 20 to 30 percent of circulating B12 is active (holotranscobalamin), and it is this fraction that is available to cells. Some individuals have total B12 within the normal range but functionally inadequate active B12 for their cellular needs. If your serum B12 is in the low-normal range and you have symptoms consistent with deficiency, discuss active B12 testing or methylmalonic acid measurement with your GP.
Folate is essential for neural tube formation in the first four weeks after conception, often before a woman knows she is pregnant. Insufficient folate during this critical window significantly increases the risk of neural tube defects such as spina bifida and anencephaly. NHS guidance recommends 400 micrograms of folic acid daily for all women planning a pregnancy and for the first twelve weeks of pregnancy. This test helps confirm that supplementation is achieving adequate serum levels, particularly for women with absorption concerns.
B12 deficiency can cause a range of neurological symptoms that may precede anaemia in some individuals. These include peripheral neuropathy (tingling, numbness, or burning in the hands and feet), proprioceptive changes (difficulty with balance), cognitive impairment ranging from brain fog to more severe memory problems, and in advanced cases, subacute combined degeneration of the spinal cord. Early identification and treatment can reverse or halt neurological deterioration; hence prompt testing when symptoms arise is strongly advisable.
High-dose folic acid supplementation is generally considered safe because folate is water-soluble and excess is excreted in urine. However, very high supplemental doses (above 1,000 micrograms per day, well above typical supplement doses) may mask B12 deficiency by correcting the anaemia without addressing the neurological component. This is one reason why testing both markers together is valuable: it ensures that treating one deficiency does not obscure the other.
