One or more B vitamin tests may be used to screen for and detect deficiencies in those with characteristic symptoms.
Testing may also be used for those who have a condition that puts them at risk of B vitamin deficiencies. This may include those with a limited or inadequate diet, those with signs of malnutrition, those being given their nutrition intravenously (parenteral nutrition), and those who have had gastric bypass surgery. Testing may also be performed on those with alcoholism or with chronic diseases associated with malabsorption, such as coeliac disease.
B vitamin testing may be useful when a person has a condition that puts them at risk for a deficiency. Those at increased risk include people who are malnourished, are chronic alcoholics, or who have a condition such as coeliac disease that is associated with malabsorption.
B vitamin toxicity rarely occurs so testing for this purpose is not often done. High concentrations of a few of the B vitamins may affect the liver or nervous system.
Test results that are low may indicate a B vitamin deficiency but will not reveal whether it is due to an inadequate supply or an inability to absorb or use available B vitamins. When a person is deficient, they often have multiple vitamin deficiencies.
If test results are normal, then it is more likely that a person's symptoms are due to another cause.
A high B vitamin concentration may be associated with vitamin toxicity. This rarely occurs and when it does, it is usually due to exposure to high doses of the vitamin.
A person may sometimes be diagnosed and treated for a B vitamin deficiency based upon clinical findings and a response to treatment, rather than testing. For instance, if a doctor suspects a B1 deficiency, he/she may prescribe B vitamin supplements and then monitor the patient to see if the symptoms resolve.
This article was last reviewed on 14 February 2012. | This article was last modified on 25 March 2013.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.