What the Active Vitamin B12 Test (Holotranscobalamin) measures
Most of the vitamin B12 in your blood is bound to a carrier protein that cells cannot use. Only a smaller fraction is bound to transcobalamin, forming holotranscobalamin (holoTC), and this is the form actually delivered to cells, which is why it is called active B12. Because holoTC tends to fall early when the supply of B12 drops, some doctors use it when a total B12 result is borderline, when symptoms such as tingling, numbness or memory change suggest deficiency despite a normal total B12, or to check whether oral supplements are being absorbed. It is a more specialised and more expensive test, and it is usually not needed when total B12 is clearly low or clearly normal. Like every B12 marker it has limitations: reduced kidney function can raise holoTC, so the result is read alongside your kidney function, blood count and symptoms. Where the picture is still unclear, a doctor may add a methylmalonic acid test, which rises when cells are short of B12.
Price: the Active Vitamin B12 Test (Holotranscobalamin) costs ₹2,000 at Pure Bliss (MRP ₹2,500), with the sample collected at our Action Area 2, New Town centre or at your home.
Who this test is for
- A borderline total vitamin B12 result
- Nerve symptoms such as tingling or numbness with a normal total B12
- Vegetarians and older adults where early deficiency is suspected
- Checking the response to oral B12 supplements
How to prepare, the sample, and when to expect the report
Preparation
Our team will tell you when booking whether the lab needs a fasting sample. Tell us if you take B12 tablets or injections and when you had the last dose.
Sample
Blood, from a vein in the arm (serum).
Reporting time
Specialised test: usually within 72 hours. We confirm the expected report date when booking.
Reading the result
Reference ranges differ between laboratories, so your report lists the laboratory’s own range beside each value. A result outside the range does not always mean illness; ask your doctor to explain it.
- Centre or home collection
- NABL-accredited Redcliffe Labs collection centre
- How collection works →