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B vitamins test

Vitamin B complex profile

B12 and folate are two B vitamins that are important for good health. Learn about the B vitamins test, how it measures vitamin b12 and folate levels, and what the results mean.

The B vitamins test is used to identify vitamin B deficiency. It is usually prescribed for those who have several symptoms that point to vitamin B deficiency. B vitamins are a group of water-soluble vitamins that includes eight different vitamins.


What is the B vitamins test?

This test measures the amount of one or more B vitamins in the blood or urine. Your body needs small amounts of these vitamins for many essential functions, including:

  • Keeping a healthy metabolism (how your body uses food and energy).
  • Producing healthy blood cells.
  • Avoid heart diseases.
  • elevate good cholesterol levels (HDL), and decrease bad cholesterol levels (LDL).
  • Nervous system functions.
  • Energy production.

B vitamins are absorbed from food or supplements, used as needed and any excess of the vitamins are removed from the body through the urine because these vitamins are water-soluble. The body can store only a small amount.

Vitamin B deficiency causes

  • Inadequate supply of foods rich in B vitamins.
  • Inability to absorb or utilize these vitamins.
  • Eating foods that inhibit vitamin b action.
  • Increasing the amounts of vitamin needed.
  • A deficiency in another mineral or vitamin that is necessary for using vitamin b complex.
  • Some diseases, such as cancer and digestive disorders.
  • Gastric bypass surgery.
  • Pregnant women.

How is it used?

The B vitamins include 8 vitamins. One or more B vitamin tests can be used to detect deficiencies in individuals with characteristic symptoms. Tests may be also prescribed for those who have a condition that puts them at risk of B vitamins deficiencies.

B vitamins tests (apart from B12 and folate) are rarely required, as treatment with a vitamin B complex is cheap and safe. Many people use vitamin B complex supplements without a B vitamins test.

Vitamin B toxicity is rare, so the B vitamin test is not often used for this purpose.

When B vitamins test is required?

Tests are usually required when you have signs and symptoms for vitamin B deficiencies. Symptoms depend on the type of vitamin that is deficient and the degree of deficiency. The most common symptoms that indicate B vitamins deficiencies are:

  • Dermatitis and skin rashes.
  • Peripheral numbness, tingling, or burning.
  • Additional fatigue.
  • Anemia.
  • Depression.
  • Memory disorders.
  • Inflamed or swallowed tongue.
  • Mouth sores.
  • Cracked lips.

B vitamins test may be also required in certain health conditions that increase the risk of deficiency, including:

  • Some chronic diseases, related to malabsorption, such as celiac disease.
  • Alcoholism.
  • Parenteral nutrition.
  • Inadequate or limited nourishment.
  • Weight loss surgery.
  • Malnutrition.
  • Certain drugs affect vitamin B levels.

Types of B vitamins test

Vitamin B12 and folate test
Types of B vitamins test.

Vitamin B levels may be checked in the blood or urine.

Test in the blood

A blood sample will be taken using a small needle from a vein in your arm by a healthcare professional. The small blood sample will be collected in a vial or a test tube. It may cause a little stinging sensation when the needle goes in or out of your vein. This process usually lasts less than 5 minutes.

Test in the urine

Vitamin B urine testing may be requested as a random urine test or a 24-hour urine sample test.

Random urine test

Your urine sample may be collected at any time of the day.

24-hour urine sample test

In this test, you have to collect all urine excreted for 24 hours. The laboratory professional will give you a container in which you will collect the urine. He will also tell you some instructions on how you should collect and store your sample. You will have to follow these steps:

  • In the morning, empty your bladder, flush that urine away and record the time.
  • Save all the urine you will pass during the next 24 hours.
  • Store the sample in the refrigerator or in a box of ice.
  • After 24 hours, return the sample container to the laboratory again to be checked.

What does the test result indicate?

Low test results refer to B vitamins deficiency but it will not indicate the reasons for this deficiency. It may be due to inadequate supply or an inability to absorb and use the available amount of vitamins. If the result shows lower levels than normal, this person will often have multiple vitamin deficiencies.

If the result of B vitamins tests is normal, this indicates that the person’s symptoms are due to another health problem. High levels of vitamin B may be associated with vitamin toxicity. This may result from high doses of vitamins supplements, but this is rare.

Read more: Acid-Fast Bacillus test


Are there any risks from the B vitamins test?

B vitamins test risks
The needle may cause a pain during taking blood sample.

Vitamin b tests in the Blood may have very little risk. You might feel slight pain or bruise at the site where the needle enters your vein, but most symptoms will disappear quickly. A urine test does not have any known risks.


Does it need special preparation?

No special preparation is needed for the test. However, you may be advised to fast overnight and/or avoid taking any vitamins supplements.


Vitamin B1 (Thiamine) test

Also known as Aneurin, or thiamine diphosphate (TDP) – the physiologically active form. Vitamin B1 is a coenzyme that helps the body to produce energy. It is also essential for glucose, lipid, amino acid, and alcohol metabolism, and to maintain the proper functions of the nervous system, muscles, and heart.

Vitamin B1 sources

  • Whole grains.
  • Pasta, rice, and fortified bread.
  • Meat especially pork and fish.
  • Legumes, such as black beans and soybeans.
  • Seeds and nuts.

Vitamin B1 deficiency causes

  • Alcohol intake.
  • Diabetic patient.
  • AIDS / HIV.
  • Older individuals.
  • Gastric bypass and other weight-loss surgeries.
  • Some medications, such as 5- fluorouracil.

Vitamin B1 deficiency may cause some symptoms, including loss of weight and appetite, confusion, muscle weakness, heart problems, and memory loss. It also causes Wernicke-korsakoff syndrome which usually affects people who drink alcohol. This problem may cause peripheral tingling and numbness with severe memory loss and disorientation.

Severe vitamin B1 deficiency causes a disease called beriberi.

  • Test name: Thiamine (thiamine diphosphate) in the blood.
  • Another way to measure: Transketolase is used to test thiamine functions.

Vitamin B2 test

The yellow water-soluble vitamin of the B complex is also called vitamin G or riboflavin. Riboflavin is essential for energy production, fat metabolism, and cellular functions and development. It is also required for other B vitamins metabolism and maintaining normal levels of homocysteine amino acid.

Vitamin B2 sources

  • Organ meats, such as kidneys and liver.
  • Eggs.
  • Green vegetables include spinach and broccoli.
  • Fortified bread and cereals.
  • Grain products.

Vitamin B2 deficiency causes

  • Deficiencies of other vitamins.
  • Drinking alcohol.
  • Malabsorption.
  • Pregnant and breastfeeding women.
  • Older and vegetarian individuals.

Vitamin B2 deficiency may cause skin disorders, hair loss, mouth sores, cracked lips, reproductive and nervous systems problems, and liver disorders. Severe riboflavin deficiency may result in anemia and cataract.

  • Test name: Riboflavin in the blood or urine.
  • Another way to measure activity: reductase in erythrocytes.

Vitamin B3 test

Also known as Niacin or Nicotinic acid. It is involved in many enzyme reactions, energy production, and metabolism. Niacin may be given in certain pharmacologic doses to lower bad cholesterol (LDL) and triglycerides and increase good cholesterol (HDL) levels.

Vitamin B3 sources

  • Meats, such as pork, fish, and beef.
  • Certain types of nuts, grains, and legumes.
  • Fortified foods.

Vitamin B3 deficiency causes

  • Undernourishment with AIDS patients.
  • Anorexia.
  • Alcohol disorders.
  • Inflammatory bowel disease.
  • Liver cirrhosis.

Severe Vitamin B3 deficiency leads to pellagra disease. Pellagra disease symptoms include dermatitis (rough skin that turns into brown or red on exposure to the sun), vomiting, constipation or diarrhea, depression, headache, and extreme tiredness.

On the other hand, pharmacological doses of Vitamin B3  may cause some symptoms, including headache, flushing,and  impaired vision. High doses may cause liver damage.

  • Test name: niacin and it’ metabolite in the blood or urine. The most reliable measure of niacin intake and body status is N1-Methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide in urine.
  • Other ways to measure: rested as NAD (Nicotinamide adenine dinucleotide) in the blood or urine.

Vitamin B5 test

Vitamin B5 or pantothenic acid helps break down carbohydrates, fats, and protein.

Vitamin B5 sources

  • Fortified cereals.
  • Mushrooms.
  • Chicken breast.
  • Organ meats.
  • Avocado.
  • Nuts and seeds.
  • Dairy products.

Vitamin B5 deficiency

Vitamin B5 deficiency is rare because it is widely distributed in many types of foods. However, an inherited disorder called pantothenate kinase-associated neurodegeneration may cause this deficiency. This deficiency result in some symptoms includes burning feet sensation and impaired healing of wounds.

  • Test name: pantothenic acid in blood or urine.

Vitamin B6 test

Vitamin B6 or pyridoxal phosphate (PLP) is a coenzyme involved in hemoglobin synthesis, amino acid metabolism, and the nervous and immune systems functions.

Vitamin B6 sources

  • Organ meats.
  • Poultry.
  • Starchy vegetables, such as potatoes.
  • Fish.

Vitamin B6 deficiency

Vitamin B6 deficiency is rare by itself, but it usually occurs with other B vitamins deficiency. An adequate amount of vitamin B2 is required to obtain the active form PLP. Alcoholism, malabsorption, smoking, autoimmune disorders, and certain antiepileptic drugs may cause its deficiency.

Deficiency may lead to itchy rashes, anemia, scaly lips, depression, and immune system weakness. Vitamin B6 deficiency in infants makes them more irritable or develop seizures.

On the other hand, an overdose may cause severe nerve damage and loss of control of movement.

  • Test name: pyridoxal phosphate (PLP) in blood.
  • Other ways for measurement: vitamin B6 functional test, 4-pyridoxic acid in the urine, and xanthurenic acid in urine.

Vitamin B7 test

Also known as vitamin H or biotin. It is necessary for protein, carbohydrate, and fat metabolism. It is essential in hormone production.

Vitamin B7 sources

  • Meat and fish.
  • Eggs.
  • Organ meats, such as the liver.
  • Sweet potato, spinach, and broccoli.

Vitamin B7 deficiency causes

Deficiency is very rare, may occur only on those who receive total parenteral nutrition with chronic alcohol abuse and some metabolism disorders, such as biotinidase deficiency.

Biotin deficiency may cause loss of body hair, skin rashes around eyes, nose, mouth, and anal areas, pink eyes, brittle nails, hair thinning, loss of body hair, and nervous system disorders. Deficiency symptoms in infants include muscle weakness, delayed development, and sluggishness. Generally, biotin doesn’t cause any harm. However, its supplement may cause false results in many lab tests.

  • Test name: biotin in blood.
  • Other ways to measure: Urinary 3-hydroxyisovalerate excretion.

Vitamin B12 and folate test

Folate is also called vitamin B9, folacin, RBC folate, or folic acid. While vitamin b12 is known as cobalamin. This test is used to diagnose one cause of anemia or neuropathy. It is also used to evaluate nutritional status or measure the effectiveness of treatment with vitamin B12 and folate.

What is being tested?

Vitamin B12 and folate are two vitamins a part of the vitamin B complex.  They are necessary for red blood cells (RBC) and white blood cells (WHC) formation, tissue repair, and DNA synthesis. They also help the body in presence of vitamin c to make new proteins.

They are nutrients that cannot be produced by the body, so must be supplied from the diet. Vitamin b12 and folate tests measure their levels in the blood sample portion. Sometimes, the amount of vitamin b9 inside RBC may be also measured.

  • b12 is found in red meat, fish, poultry, milk, yogurt, and eggs.
  • Vitamin b9 or folate refers to the natural form of the vitamin, while folic acid refers to the form present in the supplements. Leafy green vegetables, citrus fruit, dry peas and beans, liver, and yeast.

Purpose of b12 and folate test

Vitamin b12 and folate are separate tests. They are usually used together to:

  • Detect their deficiencies.
  • Diagnose certain types of anemias, such as pernicious anemia, that affect vitamin b12 absorption.
  • Help neuropathy diagnosis.
  • Evaluate your nutritional state and general health.
  • Determine the causes of behavior changes, or mental state problems.
  • Measure the effectiveness of treatment with vitamin b12 and folate supplements.

Serum folate levels may vary depending on a person’s last diet. RBC stores 95% of circulating folate, so a test to measure folate in RBCs may be also used in addition to the serum test.

Some healthcare professionals thought that the RBC folate test provides more accurate results of long-term folate status than serum folate.

When vitamin b12 and folate test is required?

b12 and folate levels may be required when a complete blood count shows a low red blood cells count, decreased hemoglobin and hematocrit, and large RBC.

Testing for b12 and folate may be also ordered if you have signs and symptoms for their deficiency, such as,

  • Muscle weakness.
  • Fatigue.
  • Diarrhea.
  • Walking trouble.
  • Loss of appetite.
  • Irregular heartbeats.
  • Breath difficulty.
  • Pale skin.
  • Peripheral numbness and tingling, especially in vitamin b12 deficiency.
  • Confusion.
  • Memory problems.
  • Irritability and paranoia.

This test may be also required in certain health conditions that put you at risk of b12 and folate deficiency. In addition to that, you will need these tests during the treatment of b12 and folate deficiency.

What does the result mean?

B vitamins test result
When you have to use vitamin B supplements?

Normal blood levels of vitamin b12 and folate indicate that you do not have a deficiency, so your signs may be due to another health problem. However, normal levels may refer to the fact that your store’s amount of vitamin b12 and/or folate has not been finished yet.

So in case of normal levels or low normal, your healthcare professional may request a methylmalonic acid (MMA) test because the deficiency is still suspected. MMA test is used for early indication of b12 deficiency.

Low b12 and folate levels indicate that you have a deficiency. Additional tests will be done to determine the exact cause of this deficiency, which may include:

  • Health conditions that decrease vitamins absorption, such as
    • Pernicious anemia, the most common cause of deficiency.
    • Gastric bypass and other gastro intestinal surgeries.
    • Inflammatory bowel diseases, such as Crohn’s disease.
    • Celiac disease.
    • Reduced stomach acid production for the long term.
  • Pancreatic insufficiency.
  • Low intake of vitamin b12 and folate-rich food.
  • chronic alcoholism.
  • Certain medications, such as methotrexate and anti-seizures.
  • Pregnancy.
  • Smoking.

On the other hand, high levels of these vitamins are not common, but some health conditions may cause this increase, such as diabetes, obesity, heart failure, and severe liver disease. Estrogen, vitamin A, and vitamin C medications can also increase b12 and folate blood levels.


Should everyone have a B vitamins test?

Most people have sufficient B vitamins blood levels, so you will not need this test unless you have B vitamins deficiency symptoms or you are at higher risk for this deficiency.


Can B vitamins levels be changed?

Your body uses the needed amount of B vitamins and eliminates any excess from the body. As soon as you have a sufficient amount of B vitamins provided through your diet. Levels of these vitamins in the blood will remain stable.

If you have B vitamins deficiency, your healthcare professional will describe b vitamins supplements.


B vitamins test and pregnancy

Vitamin B6, B9, and B12 are essential to maintain a healthy pregnancy. This test is not routinely required during pregnancy. However, Nearly all pregnant have to take prenatal vitamins, which mainly contain b vitamins, especially folic acid which helps prevent the brain and spine birth defect of the fetus, when administrated during pregnancy.


If you have any B vitamins deficiency symptoms, you should do a B vitamins test to ensure the level of the vitamins in your body and receive the correct treatment.

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