Can Recombinant Human Intrinsic Factor Be Used for Evaluation of the Vitamin B12 Absorption?
Can Recombinant Human Intrinsic Factor Be Used for Evaluation of the Vitamin B12 Absorption?
Vitamin B12 is an essential nutrient for normal DNA-synthesis and must be supplied by animal
 products. Vitamin B12 deficiency may cause anemia and irreverible neurological damage.
 Laboratory tests are used for diagnosis of vitamin B12 deficiency, and following the
 diagnosis, the cause of the vitamin B12 deficiency has to be clarified. For years a test
 called Shilling's test has been used for evaluation of the vitamin B12 absorption. However,
 the Schilling's test is no longer easy accessible because of increasing difficulties to
 obtain the radioactively labeled vitamin B12 requested, and native human intrinsic factor for
 Schilling's test II (absorption of vitamin B12 attached to intrinsic factor) is no longer
 available in most countries. Recently, human intrinsic factor unsaturated with vitamin B12
 has been expressed in the plant Arabidopsis thaliana. The purpose of this study was to
 examine whether recombinant human intrinsic factor is able to promote the uptake of vitamin
 B12 in patients with evident vitamin B12 deficiency.
Vitamin B12 is an essential nutrient for normal DNA-synthesis and must be supplied by animal
 products. Vitamin B12 deficiency may cause anemia and irreverible neurological damage.
 Laboratory tests are used for diagnosis of vitamin B12 deficiency, and following the
 diagnosis, the cause of the vitamin B12 deficiency has to be clarified. For years a test
 called Shilling's test has been used for evaluation of the vitamin B12 absorption. However,
 the Schilling's test is no longer easy accessible because of increasing difficulties to
 obtain the radioactively labeled vitamin B12 requested, and native human intrinsic factor for
 Schilling's test II (absorption of vitamin B12 attached to intrinsic factor) is no longer
 available in most countries. Recently, human intrinsic factor unsaturated with vitamin B12
 has been expressed in the plant Arabidopsis thaliana. The purpose of this study was to
 examine whether recombinant human intrinsic factor is able to promote the uptake of vitamin
 B12 in patients with evident vitamin B12 deficiency.
Inclusion Criteria:

 Patients suspected to have vitamin B12 deficiency defined as a plasma vitamin B12 below the
 reference interval (<200 pmol/L).

 Exclusion Criteria:

 Patients who were pregnant, nursing or not able to give written informed consent were
 excluded.