Rupture of some of the red blood cells (hemolysis) in the blood sample may affect test results.
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
The health care provider will usually take blood or red blood-cell folate levels when testing for megaloblastic anemias of any kind.
The blood test for levels of vitamin B12 has become much more accurate within the past few years. Now, there are fewer false-normal results, because the test only measures biologically active B12.
A Schilling test can find the cause of a vitamin B12 deficiency.
Mason JB. Vitamins, Trace Minerals, and Other Micronutrients. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 237.
Kumar N. Neurologic presentations of nutritional deficiencies. Neurol Clin. 2010 Feb;28(1):107-70.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885