folate and B deficiencies are both known to interfere with intestinal cell function, and thus cause malabsorption of B on their own, even if intrinsic factor is being made. This state would then tend to cause a false-positive test for both simple B and intrinsic factor-related B malabsorption. Several weeks of vitamin replacement are necessary, before epithelial damage to the G.I. tract from B deficiency is corrected. Many labs have stopped performing the Schilling test, due to lack of production of the cobalt radioisotopes and labeled-B test substances. Also, injection replacement of B has become relatively inexpensive, and can be self-administered by patients, as well as megadose oral B. Since these are the same treatments which would be administered for most causes of B malabsorption even if the exact cause were identified, the diagnostic test may be omitted without damage to the patient (so long as follow-up treatment and occasional serum B testing is not allowed to lapse). It is possible for use of other radiopharmaceuticals to interfere with interpretation of the test. Diagnoses References External links Chemical pathology