Vitamin B Test

B vitamins are nutrients that your body needs to work well and stay healthy. There are eight different types. A vitamin B test checks the level of one or more B vitamins in a sample of your blood or urine (pee).

All the B vitamins together are called the 'B vitamin complex.' The B vitamins are: B1, thiamine; B2, riboflavin; B3, niacin (also called nicotinic acid and nicotinamide); B5, pantothenic acid; B6, pyridoxal phosphate; B7, biotin; B9, folate (folic acid); B12, cobalamin; Each type of vitamin B plays different important roles in your body, such as helping to: Maintain normal metabolism (the process your body uses to make energy from food you eat); Make healthy blood cells; Keep your nervous system working properly; You get B vitamins from many foods, including leafy green vegetables, meats and fish, eggs, whole grains, milk, and other dairy products. A lack of vitamin B is rare in the United States, because many foods have added B vitamins. These foods include cereals, breads, and pasta.

But certain diets and health conditions can affect how well your body absorbs vitamin B. And if you lack B vitamins, it can cause serious health problems. For example, a lack of B12 can cause anemia and nerve disorders.

A lack of B vitamins is called a vitamin B deficiency. It's usually treated with supplements. But it's important to talk with your health care provider before taking vitamin B supplements.

That's because large amounts of some B vitamins can cause health problems, too. And some B vitamins may affect the way certain medicines work in your body.

Why this test is done

You may need a vitamin B test if you have symptoms that could mean you're lacking certain B vitamins. The symptoms depend on which type of a vitamin B deficiency you have.

For example, common symptoms from a lack of vitamin B6 may include:

• Itchy rashes
• Cracks at the corners of the mouth
• Scaly skin on the lips
• Swollen tongue

Common symptoms from a lack of vitamin B12 may include:

• Fatigue
• Arrhythmia (problems with the rate or rhythm of your heartbeat)
• Weight loss when you're not trying to lose weight
• Tingly or numb hands and feet (a sign of nerve problems)

You may also need vitamin B testing if you have a condition or habits that increase your risk of having a vitamin B deficiency, such as:

• Celiac or Crohn's disease
• Alcohol use disorder (AUD)
• Malabsorption syndrome
• Not eating foods that are rich in B vitamins, such as animal products (meat, eggs, and/or dairy foods)
• Having had surgery on your digestive system, including gastric bypass surgery for weight loss
• Taking certain medicines that affect how your body uses certain B vitamins

How to prepare

Before a vitamin B blood test, you may need to fast (not eat or drink) for several hours before the test. A urine test doesn't require any special preparations.

Sample type

Blood Urine

Other names for this test

vitamin B testing, vitamin B complex, thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxal phosphate (B6), biotin (B7), vitamin B12, folic acid, folate, and cobalamin test