What are the gold standard Vitamin B12 Tests?

What are the gold standard Vitamin B12 Tests?

by Jigar Parmar on Jan 22, 2023

Before we look in to lab tests which are required for diagnose a vitamin b12 deficiency We have to understand

  1. What Is a Vitamin B12
  2. What are causes of vitamin b12 deficiency and their signs and symptoms


When does your doctor ask you to do Vitamin B12 Test?

Vitamin B12 Lab investigations are mostly suggested when you have signs and symptoms of vitamin B12 deficiency or some diseases conditions like …

  • Pernicious anemia
  • Loss of appetite
  • Glossitis
  • Mouth ulcers
  • Gastritis
  • Confusion
  • Weakness
  • Loss of memory
  • Loss of balance
  • Loss of sensations
  • Mood swings
  • Tingling in hand and feet


Who needs to take a vitamin B12 test? Who is at risk for vitamin B-12 deficiency ?

  • Children
  • Old aged persons ( age above 55 )
  • Vegans
  • 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.
  • Some conditions may also affect your body’s ability to absorb vitamin b12. check such conditions.
  • Proper and confirmed diagnosis of vitamin B12 can be done by clinical standpoint and lab investigations which are given below ..


1) Serum vitamin b12 test

serum vitamin b12 test is used for diagnose vitamin b12 deficiency, This test measures the total concentration of vitamin b12 present in the blood.

How Serum vitamin b12 test performed?
  • There is no special preparation required prior to the test, it can be done any time. You should fast for 6 to 8 hours before undergoing the test.
  • An experienced technician collects the blood sample from the arm by inserting a needle into the vein.
  • This sample is then collected in a sterile tube. This sample is then subjected to further analytical techniques such as chromatography, immunoassays, in recent time radioisotope techniques to get accurate results.

Serum vitamin b12 test result and normal range:

General, Normal level of vitamin b12 are between 200-170 pg/ml or 155-126 pmol/l 170-100 pg/ml or 126-74 pmol/l indicates vitamin b12 deficiency.

Once a lab report comes, The Health care professional doctors will identify severity of vitamin b12 deficiency, they will suggest more sensitive lab investigations (given below) for confirm-sure diagnosis of vitamin b12 deficiency.


2) MMA (methylmalonic acid) test

an MMA test is most often used to diagnose a vitamin b12 deficiency because it is more sensitive than serum vitamin b12 test.

  • This test measures the amount of MMA in your blood or urine.
  • MMA is a substance made in small amounts during metabolism of body cells, metabolism is the process of how your body changes food into energy.
  • Vitamin b12 plays an important role in metabolism, if your body doesn't have enough vitamin b12 - it will make extra amount of MMA .
  • Methylmalonic acid test is also frequently ordered for screening of infants for rare genetic disorder, when the doctor suspects the presence of methylmalonic acidemia.

How MMA (methylmalonic acid) test performed?

MMA test can be done by blood sample and urine sample so .. both test is performed differently !

  1. MMA blood test: No special prior preparation is needed. During a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted,a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than six minutes.
  2. MMA urine test: This test can be done by random urine sample or 24-hour urine sample, you have to collect your urine in to urine sample collector container.

A random urine sample is a one time process, you just have to collect it any time and submit it to lab investigator.

A 24-hour urine sample is a collection of urine done throughout the whole day.

Procedure for collection 24-hour urine sample is

First of all label your name with date and time in your urine container Begin collecting the sample in the morning and note down time in the container because from then on, all the urine has to be collected in the container for the next 24 hours.Between sample collection, put the container in a cool place/refrigerator. After the sample has been collected, submit the container to the laboratory for analysis.

MMA blood/urine test result and normal range:

HIGH MMA level can be a sign of vitamin B12 deficiency, kidney disease or can be found in pregnancy.
In kidney diseases MMA is not excreted properly in urine, thus it accumulates in the blood !

Reference normal range

MMA Blood test : 53-376 nmol/l
MMA Urine test : 0.0-3.6 nmol/mol CRT (millimoles per mole of creatine)

3) Homocysteine test

a homocysteine test helps determine the amount of homocysteine in blood.

  • Homocysteine is an amino acid present in low levels in body cells. It is continuously broken down into smaller molecules by vitamin B12, B6 and folic acid.
  • A rise in blood homocysteine level is thus an indication of vitamin B12 - B6 or folic acid deficiency, use of medications such as isoniazid, penicillamine, carbamazepine, or due to smoking.
  • Increased level of homocysteine can cause thickening of arterial walls, which raises the risk of stroke and myocardial infarction.
Homocysteine  test result and normal range:
Normal range for male : 1 - 2.12 mg/l
Normal range for female : 0.53 - 2 mg/l