What It Measures#
The Vitamin B12 test (also called cobalamin test) measures the level of vitamin B12 in your blood. B12 is essential for:
- Red blood cell formation, deficiency causes megaloblastic anaemia (large, immature RBCs).
- Nerve function, B12 maintains the myelin sheath around nerves; deficiency leads to numbness, tingling, and neuropathy.
- DNA synthesis, critical for cell division and growth.
- Brain health, low B12 is linked to memory problems, confusion, and depression.
India has one of the highest rates of B12 deficiency globally, largely because a significant proportion of the population follows a vegetarian or vegan diet. Plant foods contain virtually no natural B12.
Who Should Get Tested#
- Vegetarians and vegans: the highest-risk group.
- Adults above 50: absorption of B12 from food declines with age.
- People with symptoms: tingling/numbness in hands and feet, fatigue, weakness, pale skin, mouth ulcers, or cognitive difficulties.
- Patients with anaemia detected on CBC, especially if MCV is high.
- People taking metformin (for diabetes) or proton-pump inhibitors (PPIs) long-term, both reduce B12 absorption.
- Patients with Crohn's disease, coeliac disease, or history of gastric surgery.
How to Prepare#
- No fasting required.
- If you take B12 supplements, your doctor may ask you to stop for a few days before the test, depending on the clinical question.
- Inform your doctor about all supplements and medications.
Understanding Your Results#
| B12 Level (pg/mL) | Interpretation | |-------------------|---------------| | Below 200 | Deficient: treatment needed | | 200–300 | Borderline / Grey zone. May need treatment based on symptoms | | 300–900 | Normal | | Above 900 | High, usually from supplements; rarely indicates liver disease |
If B12 is in the grey zone (200–300 pg/mL) with neurological symptoms, your doctor may order a methylmalonic acid (MMA) or homocysteine level to confirm functional deficiency.
Treatment involves intramuscular B12 injections (for severe deficiency or malabsorption) or high-dose oral methylcobalamin tablets (1,500 mcg/day).
Related Tests#
- CBC, shows high MCV (macrocytosis) in B12 deficiency.
- Iron Studies, helps differentiate types of anaemia.
- Vitamin D Test, often co-deficient with B12 in Indian populations.
- Thyroid Function Test, autoimmune thyroiditis and pernicious anaemia share an autoimmune link.
Booking & Home Collection#
Book your Vitamin B12 test on PingMeDoc with home collection. No fasting needed. Book at any convenient time. Digital reports within 24 hours.