Abstract
The technique of measurement of Co^<60>-labeled vitamin B_<12> in urinary excretion test was studied with regard to the errors and factors which influence the test results. The oral dose of 2μg was used as the standard dosage, and for "flushing" purpose 1mg of unlabeled vitamin B_<12> was given by intramuscular injection two hours later. The normal range and average value of urinary excretion at this oral dose were measured. This test seems to be of value for clinical applications, because of its practicability, provided the assumption holds true that the urinary excretion is in relative proportion to the absorption
