What is a vitamin
Vitamin B-12 is an important vitamin for many bodily
functions, such as brain health, blood cell production, and proper nerve
functioning. There are several ways to test your B-12 levels. You can get your
blood drawn or take a home urine test. These tests will look at the levels of
- overall vitamin B-12
- holotranscobalamin (holoTC)
Research suggests that MMA
may be more accurate at reading low B-12 levels because they represent active
B-12. Low B-12 levels can lead to:
- permanent nerve damage
- deteriorating brain functions
- memory loss
- temporary infertility in women
People who are obese or eat a lot of meat also tend to have
higher-than-normal levels. High levels of vitamin B-12 can be a sign of liver
disease, certain types of leukemia, or diabetes.
Vitamin B-12 deficiency is a common condition. Between 1.5
and 15 percent of Americans have low levels of vitamin B-12, according to the National
Institutes of Health. Many people, especially older adults and people with
intestinal disorders, have trouble absorbing vitamin B-12 from food and oral
When does your
doctor order a vitamin B-12 test?
Your doctor might recommend a B-12 test if you have:
- tingling in the hands and
- problems with balance
- a racing heart
- loss of appetite
You may also take this test if your doctor suspects you
might have pernicious
anemia. Pernicious anemia is a reduction in red blood cells. It occurs when
your intestines can’t absorb vitamin B-12, which is necessary for red blood
cell production. Symptoms are not often seen in people younger than 30 years
old. The average age of diagnosis is 60.
Symptoms of this condition include:
- diarrhea or constipation
- loss of appetite
- pale skin
- inflamed red tongue, or gums that bleed
High serum folate levels
Your doctor might also test your vitamin B-12 levels if you
have high serum folate levels. High serum folate levels may mask vitamin B-12
deficiency and worsen the symptoms, according to the National
Institutes of Health (NIH). Serum folate measures the level of folic acid
in the blood. Folic acid is necessary for your body’s growth and development
and the production of red and white blood cells and platelets.
Who needs to take a
vitamin B-12 test?
Your body doesn’t naturally produce vitamin B-12. It comes
from animal products like fish, meat, and dairy. People who are at risk for
vitamin B-12 deficiency are:
- older adults
- strict vegetarians
- people with diabetes
- people who’ve had gastric bypass surgery
New mothers who are breastfeeding may want to test their
vitamin B-12 levels if they have symptoms or are in the at-risk group above. If
a breast-feeding mother has low levels of B-12, her infant is at increased risk
for neurological damage and developmental problems, according to Harvard
Some conditions may also affect your body’s ability to
absorb B-12. Talk to your doctor if you have:
- pernicious anemia
disease, where your body’s immune system reacts to gluten by damaging
the lining of the intestine
- Crohn’s disease,
an autoimmune condition that causes persistent inflammation of the gastrointestinal
gastritis, a condition where your stomach lining narrows and limits
stomach acid production
Medications that may also affect the body’s vitamin B-12
Side effects and risks of a B-12 test
You might feel a pricking when your doctor or nurse inserts
the needle into your arm. But a blood draw is low risk and generally painless.
It’s also possible to feel a little sore or observe bruising on your arm for a
few days after. Alert your doctor if the pain is throbbing or if your arm
swells after the test.
Talk to your doctor before the test if you have a bleeding
disorder, such as hemophilia,
or if you’ve had problems with blood clotting in the past. It’s possible to
experience excessive bleeding where the needle punctures your skin.
It’s also important to tell your doctor about any
medications or over-the-counter drugs you’re taking, as certain drugs may
interfere with the test results.
Types of B-12 tests and how they’re performed
Preparing for a blood test
Your doctor will tell you not to eat or drink for about six
to eight hours before your test. You’ll want to make sure you’re well hydrated
on the days before the test.
During the test, your doctor will clean a small area of your
arm or elbow with an antiseptic wipe or alcohol pad. They might wrap an elastic
band around the top of your arm to increase the flow of blood. Your doctor will
then insert the needle into your vein and collect your blood.
Once enough blood is drawn, the doctor will remove the
needle and apply a bandage. Your blood sample is then taken to a lab to measure
for vitamin B-12 or other markers, like holoTC.
Preparing for the home tests
It’s possible to test your B-12 levels at home. Home test
kits cost about $50.00 each and can be purchased online. Most home kits test your
urine for the presence of MMA, which is linked to early stages of a vitamin B-12
You may need to send your urine sample to a laboratory.
These kits will include a jar and mailing instructions. Others will include
test strips that you dip into your urine sample yourself, allowing you to read your
results right away.
Interpreting B-12 test
Both high and low levels of vitamin B-12 may indicate an
underlying problem. Low levels of B-12 can suggest anemia, an internal parasite,
and hyperthyroidism. High levels of B-12 may increase your risk for cancer,
according to Medical
High levels of B-12 can also be a sign of:
- liver disease
- certain types of leukemia
- kidney failure
It’s also possible to have low or high levels of vitamin
B-12 without other health concerns. Most health conditions will have additional
symptoms other than abnormal vitamin B-12 levels.
Normal ranges can also vary from laboratory to laboratory,
so it’s important to discuss your results with your doctor.
Vitamin B-12 results
For urine tests, a normal range for MMA is under 3.8 mcg/mC.
If you have higher levels, you may have B-12 deficiency.
The normal range for holoTC is 23–100 pmol/L. Low holoTC is
an early indicator of low B-12.
How to manage your B-12 levels
For people with high levels of B-12, treatment involves
adjusting your diet. This may mean eating less animal products like meats,
dairy, and seafood.
If you’re diagnosed with a B-12 deficiency, the goal of
treatment is to increase your level of vitamin B-12. Your treatment may
- vitamin B-12 injection, with more frequent
injections for those with severe deficiencies
- daily vitamin B-12 supplements, such as Cyanocobalamin,
which is a manmade vitamin B-12
- regular administration of liquid B-12 through
- adhering to a diet rich in vitamin B-12
If your B-12 deficiency is the result of an underlying
medical condition, your doctor will treat that condition first.
States where vitamin B-12 supplements are most prescribed
What to eat to
prevent vitamin B-12 deficiency
Many cases of B-12 deficiency are rooted in underlying
health problems, but it’s possible to take preventative measures. Preventative
measures include paying close attention to your diet, especially if you’re
vegetarian or vegan.
One serving of fortified breakfast cereal may fulfill 25 to
100 percent of your daily intake value, depending on the brand. Three ounces of
cooked salmon has about 80 percent of your daily intake value.
You can also find B-12 in:
- liver, pork, and beef
- chicken and poultry
- fortified soymilk
- dairy, such as milk, yogurt, cheese
- vitamin supplements
Vegetarians and vegans may also find some soy products, miso,
and sea vegetables with B-12, but these don’t contain significant amounts of
How much vitamin B-12 do you need?
How much B-12 you need depends on your age and if you are
pregnant or breastfeeding. The table below shows how much
While high vitamin B-12 may be a sign of other conditions,
consuming excess vitamin B-12 doesn’t appear to cause any adverse health