“…Recent studies of different workers on 57Co-vitamin B12 absorption-plasma level tests gave similar results but with lower plasma radioactivity values and in some cases equivocal results [1,3,6,9,11,13,14], Probably this is due to use of vitamin B12 with lower specific activity and lower dosage (0.5 //c/0.5 ng to 1.0 fic/l.O //g) and differences in methods of calculation of absorbed vitamin B12. This has generally been done per 1000 ml of plasma [1,11,13,14] or expressed as cpm in 4 or 5 ml of plasma [6,9]. A flushing dose of cold vitamin B12 injection was frequently administered at different time intervals and occasionally carbocal was also given before the test [1,3].…”