RALPH CARMEL, M.D.
This content is PDF only. Please click on the PDF icon to access.
To the editor: In the October 1979 issue Drs. Jacobson and Onstad (1) described a Schilling test artifact caused by inactive commercial intrinsic factor. That report is an important reminder of the vagaries of commercial preparations and illustrates why each laboratory should monitor its methods and materials and not abandon this function to the suppliers. Similar intrinsic factor potency problems in a different laboratory procedure have also contributed to artifactual results in the radioassay for serum vitamin B12 (2).
Still another intrinsic factor problem in testing vitamin B12 absorption can be mentioned. Confusing results may occur with the so-called "double-isotope"
CARMEL R. The Schilling Test. Ann Intern Med. 1980;92:570–571. doi: 10.7326/0003-4819-92-4-570_2
Download citation file:
Published: Ann Intern Med. 1980;92(4):570-571.
Copyright © 2019 American College of Physicians. All Rights Reserved.
Print ISSN: 0003-4819 | Online ISSN: 1539-3704
Conditions of Use