Test Quick Guide

B vitamins, also called the vitamin B complex, includes several types of vitamins that play vital roles in the body. B vitamins help your body use food and energy, make healthy blood cells, and support proper functioning of the nervous system.

Vitamin B testing checks for inadequate levels of B vitamins in the body. Although vitamin B deficiencies are rare in the United States, your health care provider may order vitamin B testing if a deficiency is suspected. Vitamin B testing requires a sample of blood or urine.

About the Test

Purpose of the test

Vitamin B testing is performed to check for vitamin B deficiencies. A vitamin deficiency means that the body lacks adequate amounts of an important nutrient. Testing is most often diagnostic, but may be used for screening certain patients:

  • Diagnosis: Vitamin B testing is usually a diagnostic test because it is ordered when symptoms of a vitamin B deficiency are present. Test results can help your health care provider diagnose or rule out a vitamin B deficiency.
  • Screening: In some cases, screening for a vitamin B deficiency is performed in patients without symptoms. This type of testing may be recommended for people who have a condition that puts them at an increased risk for having a nutritional deficiency, such as celiac disease or a past weight loss surgery.

What does the test measure?

B vitamins are a group of nutrients needed by the human body for healthy functioning. Because these vitamins cannot be made by the body itself, they must be obtained through an individual’s diet.

B vitamins are found naturally in many foods including eggs, meats, milk, green vegetables, and nuts. In addition, many foods, such as bread, cereals, and pasta, have B vitamins added to them. These foods are referred to as fortified. B vitamin deficiencies are rare in the United States, and are most often seen in people who have conditions that make it difficult for them to absorb adequate amounts of vitamin B.

Types of B vitamins

There are several types of B vitamins in the B vitamin complex.

Vitamin B1 is also called thiamine or thiamin. Vitamin B1 helps the body change the food you eat into energy that your body can use. Vitamin B1 also plays an important role in the growth, development, and function of the cells in your body. It is needed for normal functioning of the muscles and nervous system.

Also known as riboflavin, vitamin B2 plays an important role in helping you absorb energy and nutrients from your food. It also plays an important role in helping your body metabolize medications.

Vitamin B3, also called niacin, niacinamide, or nicotinic acid, is needed for the nervous system, skin, and digestive system to function normally. It also helps the body change food into energy. Niacin helps increase the level of HDL cholesterol, called “good cholesterol”, and decrease the level of unhealthy fat in your blood.

Pantothenic acid, a common name for vitamin B5, helps turn food into usable energy. It is especially important in the process of making and breaking down fats. It is also needed for growth as well as for the production of hormones and cholesterol. Vitamin B5 deficiency is extremely rare.

Also known as pyridoxal phosphate, vitamin B6 is needed for many chemical reactions that occur during metabolism, the processes of storing and using energy in the body. It also helps with brain development during pregnancy and infancy. Additionally, vitamin B6 helps in the process of making antibodies, which are needed to fight viruses and other infections.

Vitamin B7, also known as biotin, is needed for growth, as well as to help the body break down and use food. Biotin is often promoted as a supplement to improve the health and appearance of your hair, skin, and fingernails, but there is little scientific evidence proving these claims. Biotin deficiency is very rare in the U.S.

Commonly called folate, vitamin B9 is important for the production of genetic material including DNA. Folate is also needed as the cells in the body divide and to form new red blood cells. Due to food fortification programs, folate deficiency is rare.

Vitamin B12 is also called cobalamin or cyanocobalamin. This vitamin is important for metabolism, the creation of red blood cells, and in the health of the central nervous system. Vitamin B12 is also important in the creation of DNA.

When should I get a Vitamin B test?

Your health care provider may order a vitamin B test if you have symptoms of a vitamin B deficiency. Although symptoms may vary depending on which vitamin is deficient, it is common for vitamin B deficiencies to occur together and the symptoms often overlap.

Certain people are at a greater risk of developing a vitamin B deficiency because of risk factors. Risk factors are anything that increase your risk of developing a disorder. Sometimes doctors will order screening tests for patients with risk factors for developing a vitamin B disorder.

Common symptoms and risk factors for B vitamin deficiencies include:

Sometimes your health care provider will diagnose you with a vitamin B deficiency without testing. Instead, the diagnosis is based upon your symptoms and the findings of a physical examination, as well as your response to treatment. This method of detecting a vitamin B deficiency, called a clinical diagnosis, is commonly used in several circumstances, including suspected deficiencies of vitamin B1, vitamin B6, and vitamin B7.

Finding a Vitamin B Test

How to get tested

Vitamin B testing is usually ordered by a health care provider. Blood or urine samples may be supplied at a doctor’s office, a laboratory, a hospital, or other medical setting. Certain types of urine samples may be collected at home or in a hospital, and then taken to a lab.

Can I take the test at home?

Commercial tests to check your levels of certain B vitamins are available at this time. These tests provide the materials you need to take a finger prick sample of blood and return it to the company providing the kit. When the sample is received, your blood levels of certain B vitamins will be evaluated in a lab. Currently, kits are available that test for several B vitamins, including:

  • Vitamin B6 test kit
  • Vitamin B9 test kit
  • Vitamin B12 test kit

It is important to discuss at-home vitamin B testing with your health care provider as the results of at-home tests are not a substitute for testing performed by a doctor.

How much does the test cost?

The cost of vitamin B testing depends on several factors including:

  • How many vitamins are tested
  • Whether a blood or urine test is performed
  • Where you have your sample taken
  • The laboratory used to analyze your sample
  • Whether other measurements are included
  • Whether you have health insurance
  • Whether a comprehensive vitamin blood panel is performed

Testing costs may include an office visit, a fee for drawing your blood or collecting your urine, and the laboratory fee for analyzing your sample. Often, these costs are covered by insurance when the test is prescribed by your health care provider. You can check with your insurance plan for coverage details including whether you are responsible for a copayment or deductible.

Taking a Vitamin B Test

Different types of samples may be required for vitamin B testing:

  • Blood: Blood samples are usually taken from a vein in your arm, although other options may also sometimes be used.
  • Random urine: A random urine sample may be collected at any time of day.
  • 24-hour urine: A 24-hour urine sample is a collection of all urine produced over a 24-hour period, using a container provided by a doctor or laboratory.

Before the test

Your health care provider may instruct you to fast prior to vitamin B blood testing. Fasting means you should not eat or drink for a certain time period, usually eight to twelve hours, before the test. Follow all instructions provided by your doctor or nurse.

During the test

The process of having a test sample collected depends on the type of test being performed:

  • Blood test: A health care professional will remove a small sample of blood from a vein in your arm. After your skin is pierced with a small needle, blood is collected in a vial or test tube. You may feel a slight sting when the needle is inserted. The test usually takes only a few minutes.
  • Random urine test: Random urine samples can be collected at any time, usually at a doctor’s office or lab. You will be given a labeled container, and directed to a bathroom where you can provide a sample in privacy. You may be given sterile wipes to clean the area around your urethra, the opening where urine leaves the body, before providing your sample.
  • 24-hour urine test: You will be given a special bag or container for this test. On the first day, your first urine will be passed into the toilet in the morning. After that, all urine will be collected in the special container. The container or bag should be stored in a refrigerator or a cool place during the collection period. On the second day, you will urinate into the container in the morning, then seal or cap it according to directions.

After the test

There are no special precautions or warnings after a test sample is collected.

After a blood test, pressure is applied to the site where the blood was removed with a piece of cotton, gauze or bandage to stop any bleeding that may occur. Next, a bandage is applied to the site. You may resume your normal activities, including driving, immediately after the test.

Vitamin B Test Results

Receiving test results

Your health care provider may share your vitamin B test results with you at an appointment or over the phone. In some cases, you may be able to access results through an online portal or a copy of your test results will be mailed to you. Vitamin B results are typically available within a few business days.

Interpreting test results

Your test report will show your level of the B vitamin or vitamins being tested, the units of measurement used, and the reference range the lab provides to interpret your results. A reference range is a range of results that is expected in healthy people. Levels that fall outside the reference range are typically flagged as high, low, or out of range.

Your health care provider will use your test results to determine whether you have a vitamin B deficiency. If test results are normal, your symptoms may be due to other causes. Laboratory-proven deficiencies are usually treated with supplements taken by mouth, but may require intravenous treatment in some severe cases.

Are test results accurate?

Because vitamin B deficiencies are not common in the U.S., testing for B vitamins has a limited role in medical care. When testing is used, some challenges exist with respect to obtaining meaningful measurements of vitamin B levels. Examples of these challenges include:

  • Reference ranges are unclear for some B vitamins and even people whose levels of B vitamins are within the reference range of a given laboratory may have a deficiency.
  • Some B vitamin tests may be influenced by what you have eaten recently, so test results may not be able to detect a deficiency. Test results are also affected by inflammation in the body.

If you have questions or concerns about the accuracy of your test result, talk to your doctor for more information.

Questions for your doctor about test results

You may wish to ask your doctor the following questions about your vitamin B test results:

  • What B vitamins were included in my test?
  • Did my test results suggest any deficiencies?
  • Based on my test results, do you believe my symptoms are caused by more than one deficiency?
  • Will additional testing be necessary?
  • What do you think is the most likely cause of my vitamin deficiency?


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