Vitamin B12 Deficiency: Symptoms, Normal Range & Test Price

Vitamin B12 deficiency means your body does not have enough usable vitamin B12 to build healthy red cells and keep your nerves working. Laboratories usually treat a level below 200 or 250 pg/mL as low.¹ It can cause tiredness, pins and needles, a sore red tongue and poor memory.² In Indian studies it turns up far more often in vegetarians.³

Set your result beside the interval your laboratory prints and beside the clinical bands below. Each number on this page carries its source.

What are the symptoms of vitamin B12 deficiency? Copy link

The common symptoms of vitamin B12 deficiency are unexplained tiredness, pins and needles or numbness, a sore red tongue, and trouble with memory or concentration.²

They build slowly. Your body stores 1 to 5 mg of B12, so a shortfall can take several years to show.¹ What happens if vitamin B12 stays low is harm to both blood cells and nerves, and the two do not always arrive together.

Doctors group the signs by the part of the body they affect.^{2, 1, 4, 5}

• Blood: tiredness, palpitations and pale skin from anemia, a shortage of healthy red cells
• Nerves: pins and needles, numbness, poor balance, falls and an unsteady walk
• Mouth and skin: a sore, red tongue, called glossitis, or patches of darker skin
• Mind: poor concentration, short-term memory loss, low mood or anxiety
• Eyes: blurred vision or a blind patch when the optic nerve is involved

How often each sign appears depends on who is counted. In a north Indian hospital series of 220 people treated for B12 deficiency, 98.18 percent had pins and needles and 87.73 percent had anemia.⁶ Skin problems from vitamin B12 deficiency were recorded in 38.18 percent.⁶

Those patients were ill enough to reach a hospital's medicine department, so milder cases will look different.

Can B12 deficiency damage nerves before anemia shows? Copy link

Yes. Nerve and mental symptoms from B12 deficiency can appear while your hemoglobin level and red cell size are still normal.^{2, 1} The UK guideline tells doctors to keep the diagnosis open when anemia is absent.²

A 1988 series studied 141 patients with nerve or psychiatric problems caused by B12 deficiency. Of these, 40 had no anemia or no enlarged red cells, which is 28 percent. In 19 of them, both the hematocrit, the share of blood made of red cells, and the red cell size were normal.⁷

A 2019 review looked at people with a low B12 in Western and Chinese data. Under 20 percent of them showed the classic large-cell anemia.⁸ In that classic picture the MCV, the average red cell size on a complete blood count, climbs above 100 fL.⁹

Waiting for that picture can cost you time. Numb feet or a slipping memory can justify a B12 test even when your blood count is normal. That holds more strongly if you eat little animal food or take metformin long term.²

Speed matters because nerves heal slowly. Neurological changes can become irreversible when the deficiency runs on, which is why early diagnosis is stressed.^{1, 10}

Which blood test checks vitamin B12? Copy link

A serum vitamin B12 test, also called total B12 or serum cobalamin, is the usual first test. It is run on the liquid part of one blood sample from a vein.² Some laboratories offer active B12, the fraction your cells can take up, as the first test instead. Its full name is holotranscobalamin.

Laboratories differ on fasting. MedlinePlus, the US National Library of Medicine's patient service, advises no food or drink for about 6 to 8 hours beforehand.¹¹ Go by what your booking confirmation says.

Give the sample before you start B12 tablets or injections.² A supplement can raise the number without fully treating a deficiency, and the result becomes harder to read. Tell the laboratory about any B12 product you already use, and about metformin or acid-reducing medicines.^{2, 11}

Nitrous oxide is a special case. When recreational use is the suspected cause, NICE asks for methylmalonic acid or homocysteine as the first test in place of a B12 level.² Both are markers that rise when cells lack B12.

What is the vitamin B12 normal range? Copy link

No single vitamin B12 normal range exists, because each laboratory sets its own interval and prints it on the blood test report. As a guide, the 2024 NICE guideline reads a total B12 above 350 pg/mL as deficiency unlikely. It reads 180 to 350 as indeterminate and below 180 as confirmed deficiency.²

NICE allows a laboratory's own validated thresholds in their place where local values differ substantially.

Other bodies draw the lines in different places. Compare your result with the row that matches the unit on your report.

Vitamin B12 normal range in pg/mL and pmol/L

Reports print pg/mL, ng/L or pmol/L. The first two give the same number. To convert pg/mL to pmol/L, multiply by 0.738, so 200 pg/mL equals 148 pmol/L.¹²

Do normal B12 levels differ by age or in females?

Normal vitamin B12 levels are not split by age or by sex in the NICE table. The same bands are applied to adult men and women.² Pregnancy is the exception. Total B12 falls during pregnancy even without deficiency, so NICE asks for active B12 as the first test.²

What does a borderline B12 result mean? Copy link

A borderline B12 result, 180 to 350 pg/mL on the NICE bands, means deficiency is possible and the number alone cannot settle it.² What follows depends on whether you have symptoms.

If you do, NICE suggests a second test for methylmalonic acid (MMA), a substance that builds up when cells lack B12.² The US National Institutes of Health reads an MMA above 0.271 micromol/L as a pointer to deficiency.¹ Homocysteine above 15 micromol/L points the same way, though folate deficiency raises it too.^{1, 2}

If you have no symptoms, the guideline's advice is to seek help should any develop.² NICE also suggests considering treatment on a borderline result if you are pregnant or breastfeeding, have had surgery that affects absorption, or have a condition that could worsen quickly.²

A result inside the range is less final than it looks. Assays, the laboratory methods, can read falsely normal in pernicious anemia, in up to 35 percent of patients by one estimate.¹³ B12 tablets taken before the test lift the level as well.²

Where the lower line belongs is still being studied. A 2025 study from the University of California, San Francisco tested 231 healthy older adults with a median, or midpoint, age of 71.2. Their median B12 was 414.8 pmol/L.¹⁴

Lower levels went with slower visual nerve signals and more white-matter change on brain MRI. Only two participants sat below the 148 pmol/L deficiency line.

That study was observational, meaning it measured people without changing their treatment, and it was small. It cannot show that a low-normal B12 caused the changes, and it proposed no new cut-off.

Why is folate tested with vitamin B12? Copy link

Folate is the vitamin sold in tablets as folic acid. It is tested with B12 because a shortage of either one causes megaloblastic anemia, an anemia with oversized red cells.¹⁵ The two results are read together.

MedlinePlus lists a normal serum folate of 2.7 to 17.0 ng/mL and asks for 6 hours without food or drink before the sample.¹⁶ Compare your folate result with the interval your laboratory prints as well.

The pairing protects your nerves. Large amounts of folic acid can correct the anemia of B12 deficiency while the nerve damage continues. A normal blood count on folic acid can therefore hide the problem.¹⁵ Ask for a B12 level before a large-cell anemia is treated with folic acid alone.

What is the vitamin B12 test price in India? Copy link

The Central Government Health Scheme (CGHS) pays ₹600 for a vitamin B12 assay in Tier I cities when the laboratory is accredited. It pays ₹510 when it is not. Both rates took effect on 13 October 2025.¹⁷ They fall by 10 percent in Tier II cities and by 20 percent in Tier III.¹⁷

These are the amounts the scheme reimburses for its members. Read them as a public reference point, because they do not cap what a private laboratory charges you.

One government teaching hospital publishes a lower charge. The user charges of AIIMS Raipur list vitamin B12 at ₹100 for general ward and outpatient patients, and ₹200 in the paying ward.¹⁸

Private prices spread widely. On 3 October 2026, the public booking pages of seven private providers listed a vitamin B12 test at about ₹490 to ₹1,690.¹⁹ Some providers quoted different prices by city, and several showed a discount against a higher list price. Compare before you book.

Follow-up tests are billed separately. On the same CGHS list a folic acid assay is ₹650 and homocysteine is ₹650. The assay used to check for vitamin D deficiency is ₹1,000.¹⁷

If the two assays are billed separately at those Tier I accredited rates, the price of a vitamin D and B12 test together comes to ₹1,600. That is a reimbursement total. Private laboratories set their own prices for combined panels. When B12 arrives inside a health checkup package, you pay the package price.

What causes vitamin B12 deficiency? Copy link

Vitamin B12 deficiency comes from too little B12 in food, from poor absorption in the stomach or small intestine, or from a medicine that interferes.² Several of these can apply to you at the same time.

• Diet: little or no animal food, since plants do not naturally contain B12, and a strict vegan diet can run stores down in about three years^{1, 9}
• Stomach and gut: autoimmune gastritis, the condition behind pernicious anemia, celiac disease, and surgery that removes or bypasses part of the stomach or the last stretch of small intestine²
• Medicines: metformin, and the acid reducers called proton pump inhibitors and H2 blockers²
• Nitrous oxide: inhaling laughing gas for a high, which the FDA, the US drug regulator, links to B12 deficiency, numbness and paralysis²⁰

How much does metformin lower B12?

Metformin, a first-line tablet for type 2 diabetes, lowers B12 in a minority of the people who take it. A US trial followed adults with a raised fasting blood sugar and excess weight for years.

At five years, 19.1 percent of those on metformin had a low or borderline-low B12, meaning 298 pg/mL or under, against 9.5 percent on placebo.²¹ Each extra year of use raised the odds of deficiency by 13 percent.

The American Diabetes Association's 2026 standards advise doctors to consider periodic B12 checks during long-term metformin use, and yearly monitoring after more than four years.²² The UK medicines regulator tells patients to keep taking metformin while the B12 is corrected.²³

Do acid-reducing medicines lower B12?

Long-term acid suppression is linked with B12 deficiency. A California study compared 25,956 people who had the deficiency with 184,199 who did not.²⁴

Two or more years of proton pump inhibitors, such as omeprazole and pantoprazole, carried 1.65 times the odds. For H2 blockers the figure was 1.25. The design was observational, so it shows a link and cannot prove cause.

Why is vitamin B12 deficiency common in India? Copy link

Vitamin B12 deficiency is common in India partly because many diets contain little animal food, and plant foods do not naturally supply B12.¹ In a Pew Research Center report published in 2021, 39 percent of Indian adults described themselves as vegetarian.²⁵

The national numbers cover the young. India's national nutrition survey of 2016 to 2018, the CNNS, defined deficiency as a level under 203 pg/mL. It found this in 13.8 percent of children aged 1 to 4 and in 17.3 percent aged 5 to 9. Among adolescents aged 10 to 19 the figure was 31.0 percent.¹²

For adults the evidence comes from regional studies. Among 630 apparently healthy urban adults in South India, 35 percent were deficient. The figure was 54 percent in vegetarians and 31 percent in people on a mixed diet, so diet explains only part of it.³

In and around Pune, 67 percent of 441 middle-aged men had a level under 150 pmol/L.²⁶

Treat single-area figures with care. A north Indian figure of 47 percent comes from 267 laboratory records in one small city, a group already sent for a test.²⁷

Dairy helps but may not close the gap. Milk sampled in Pune carried 2.5 to 3.85 micrograms of B12 per liter, against an adult allowance of 2.2 micrograms a day.^{28, 29}

In a small Pune trial with no comparison group, 29 deficient vegetarians drank 400 mL of buffalo milk daily for 14 days. Their median B12 rose from 92.5 to 122 pmol/L, still under the 148 line.²⁸

Fortified staples add a little. Indian standards set fortified rice and wheat flour at 0.75 to 1.25 micrograms of B12 per kilogram.³⁰ The government has approved fortified rice across its food schemes up to December 2028.³¹ As arithmetic, 300 g of such rice a day supplies roughly 0.2 to 0.4 micrograms.

What is pernicious anemia? Copy link

Pernicious anemia is an older term, most often used for severe vitamin B12 deficiency linked to autoimmune gastritis. In autoimmune gastritis the immune system attacks the stomach cells that make intrinsic factor, the protein B12 needs for absorption.^{2, 9}

Antibodies against intrinsic factor itself can add to the block.¹³ B12 from food then goes largely unabsorbed, whatever you eat. Pernicious anemia is caused by that deficiency of B12, and what causes it in turn is the immune system.

NICE no longer uses the term in its recommendations. Its reasons are that truly life-threatening anemia is now extremely rare, and that the name gets confused with autoimmune gastritis itself.² You can have the deficiency, and nerve symptoms, with no anemia at all.

When anemia does develop it is megaloblastic anemia, which is caused by a deficiency of vitamin B12 or folate.¹⁵ Megaloblastic anemia symptoms are those of anemia in general, such as tiredness and pale skin, with the nerve symptoms of B12 deficiency on top.¹

Studies that use the older name put pernicious anemia at about 2 percent of people over 60 to 70. It is less common in people of Asian descent than in other groups studied.¹³

The blood test looks for anti-intrinsic factor antibodies. A positive result is close to 100 percent specific. The test picks up only 40 to 60 percent of cases, so a negative result leaves autoimmune gastritis possible.^{13, 2} NICE recommends B12 injections for life.²

Can vitamin B12 deficiency be a sign of cancer? Copy link

Usually no. The recognized causes of a low B12 are diet, poor absorption and certain medicines.²

One of those causes carries a cancer risk of its own. Autoimmune gastritis raises the risk of gastric neuroendocrine tumors, a type of stomach tumor, and may raise the risk of stomach cancer.² The low B12 and the tumor risk both come from the stomach condition, so the B12 result is not the warning sign.

A pooled analysis of 27 studies put stomach cancer incidence in pernicious anemia at 0.27 percent for each year a person was followed. People with pernicious anemia had about 6.8 times the usual risk, an imprecise estimate that could lie anywhere from 2.6 to 18.1.³²

In practice, new or worsening stomach symptoms in someone with autoimmune gastritis deserve a prompt review.²

How is vitamin B12 deficiency treated? Copy link

Vitamin B12 deficiency is treated by replacing the vitamin, as tablets or as injections into a muscle, and the cause decides the route.² Your doctor sets the dose and the schedule.

• Diet-related deficiency: NICE suggests considering tablets, along with advice on food sources²
• Autoimmune gastritis, or surgery that removed the whole stomach or all of the last part of the small intestine: injections for life²
• Severe deficiency or nerve symptoms: injections should be considered³³

Trials support tablets for many people. A 2018 Cochrane review of three trials and 153 participants found low-quality evidence that tablets and injections raise B12 levels to a similar degree.³⁴

A Madrid trial enrolled 283 people aged 65 or over. At 8 weeks, more than 90 percent in both groups had reached a normal level. By 52 weeks both groups had stepped down to maintenance doses, weekly tablets or monthly injections. The figures were then 73.6 percent on tablets and 80.4 percent on injections.³⁵

A 2025 pooled analysis of 16 studies and 6,098 participants again found no significant difference between oral, under-the-tongue and injected B12. The studies varied widely, which weakens that conclusion.³⁶

Only about 1.3 percent of a 1,000 microgram tablet is absorbed.¹ By arithmetic that is roughly 13 micrograms, several times the Indian daily allowance of 2.2.²⁹

Supplements come as methylcobalamin, cyanocobalamin or hydroxocobalamin. No evidence shows that one form is absorbed better than another.^{1, 37} B12 has no set upper intake limit, because its toxicity is low.¹ Expect a review about 3 months after you start, or at 1 month if you are pregnant or breastfeeding.²

How long to recover from vitamin B12 deficiency? Copy link

Recovery from vitamin B12 deficiency takes weeks for the blood and months for the nerves. Symptoms can start to improve within 2 weeks of treatment, though this may take up to 3 months.²

• About 1 week: new red cells, called reticulocytes, begin to respond⁵
• About 8 weeks: the anemia and the red cell size are expected to be back to normal^{5, 4}
• 6 weeks to 3 months: pins and needles and other nerve symptoms improve^{5, 4}
• 3 to 12 months or longer: spinal cord involvement, where recovery is slower¹⁰

Your symptoms can get worse for a short while at the start.² If nothing has changed by the 3-month review, or new symptoms appear, go back sooner.

If your hemoglobin was low, a repeat blood count at about eight weeks shows whether it has come back up.⁴ Raising a low hemoglobin depends on treating its actual cause, and B12 is one of several.

Nerve damage that has gone on for a long time may not fully reverse.¹⁰

What to eat for vitamin B12 deficiency? Copy link

Eat animal-source or fortified foods, because those are the foods that contain B12. Milk, yogurt or curd, eggs, fish and meat supply it naturally.¹ US food tables list about 1.3 micrograms in a cup of milk and 0.5 in one egg.¹

Milk measured in Pune was lower. By arithmetic it works out to about 0.6 to 0.9 micrograms for a 240 mL cup.²⁸

Fruits, vegetables and grains do not naturally contain B12.¹ A few unusual plant foods, such as some dried seaweeds, do carry it. Spirulina is a poor substitute. Tablets that were tested often contained large amounts of pseudovitamin B12, a look-alike that is inactive in humans.³⁸

Diet alone may be too slow once you are deficient. In a small trial in Pune, 14 days of daily milk raised the median B12 of deficient vegetarians but left it below the cut-off.²⁸ Replacement usually comes first for that reason, with food as the long-term safeguard.

What does a high vitamin B12 level mean? Copy link

A high vitamin B12 level usually reflects B12 tablets or injections. Without supplements it needs an explanation, because known causes of a high B12 include liver disease, kidney disease and certain blood cancers.^{39, 11}

What happens if vitamin B12 is high depends on which cause is found.

A harmless cause exists too. Macro-B12 is B12 bound to antibodies, which clears slowly and inflates the reading. A 2026 Dutch laboratory series found it in 24 percent of 72 people whose level exceeded 1,476 pmol/L, about 2,000 pg/mL.³⁹

Persistence is what doctors weigh. A level above 1,000 pg/mL on two measurements has been associated with solid tumors and blood cancers.³³ That association does not mean a high B12 level diagnoses cancer. If your level is high and you take no B12, ask your doctor whether it should be repeated.

What is the treatment for high vitamin B12?

No treatment is aimed at the number. Care is directed at the cause, so how you reduce B12 levels depends on what raised them. To decrease vitamin B12 that is high from supplements, your doctor may review the dose. Excess B12 is usually removed in the urine.¹¹

No upper limit has been set for B12 intake, because its potential for toxicity is low.¹

Does pregnancy change vitamin B12 levels? Copy link

Yes. Total B12 tends to fall during pregnancy, sometimes to subnormal levels, and usually returns to normal after delivery.¹ NICE therefore uses active B12 as the first test in pregnancy.²

A Bengaluru cohort was tested at about 12 weeks of pregnancy. In it, 63.2 percent of women had a B12 below 148 pmol/L, and 40.8 percent of their newborns were deficient at birth. Deficient mothers were about twice as likely to have a deficient newborn. The study observed pregnancies and assigned no treatment.⁴⁰

India's Anemia Mukt Bharat guidelines, re-issued in June 2026, list preventive iron and folic acid for pregnant women. The government's summary of them does not mention B12.⁴¹

Babies who are exclusively breastfed by mothers eating no animal foods can run short early in life.¹ If you are pregnant or breastfeeding and eat little animal food, ask your doctor at your next visit whether B12 testing or supplementation is appropriate.

Which symptoms of B12 deficiency are urgent? Copy link

See a doctor promptly if nerve or vision symptoms are new or getting worse. When large-cell anemia comes with neurological symptoms, NICE tells doctors to start B12 without waiting for test results.²

• Numbness or weakness that is spreading
• New trouble walking or keeping your balance
• Blurred vision or a blind patch
• New confusion or a sharp change in memory
• Any of these after inhaling nitrous oxide

This article is general health information for readers in India and does not diagnose anything. Every laboratory sets its own reference interval, so check your result against that interval with your doctor. Vitamin B12 doses and injections are prescribed on the basis of your own results. Prices are the published rates and list prices named in the references, checked on 3 October 2026, and they change. Sapiens is operated by Pangaea Sciences Private Limited, Hyderabad. Report an error on this page.

Written by Dr. Tarun Reddy, MBBS · Registered medical practitioner (TSMC/FMR/36195) at Sapiens · Published 4 October 2026 · Editorial standards