disorders of nutrition
Vitamin B12 Deficiency
Diagnosis of Vitamin B12 Deficiency
Blood tests Sometimes endoscopy Usually, vitamin B12 deficiency is suspected when routine blood tests detect large red blood cells. Doctors sometimes suspect it when people have typical symptoms of nerve damage, such as tingling or loss of sensation. If the deficiency is suspected, the level of vitamin B12 in the blood is measured. Usually, doctors also measure the blood level of folate to rule out Folate Deficiency , which can also result in large red blood cells. If vitamin B12 deficiency is confirmed in an older person, no other tests are done because the cause, such as low stomach acidity, is usually not serious. In a younger person, other tests, including other blood tests, may be done to determine the cause. Endoscopy (use of a flexible viewing tube to directly examine internal structures) may be done to check for destruction of stomach cells that produce intrinsic factor. 