The use of hydroxocobalamin in the Schilling test

Hydroxocobalamin and cyanocobalamin have been compared as the 'flushing dose' in the Schilling test. In healthy, haematologically normal subjects excretion of the test dose was greater following a hydroxocobalamin flushing dose than following a cyanocobalamin flushing dose, and to a lesser extent this was also true in patients requiring investigation. There were occasional discrepant results, but in general it appears that, although reference values differ, hydroxocobalamin is a suitable replacement for cyanocobalamin in the Schilling test.