Patent ID: 6555388
Filing Date: 2003-04-29
Classification: G01N

Abstract:
A method to determine an amount of vitamin B12 in a fluid sample, the fluid sample comprising at least some of the vitamin B12 bound to endogenous intrinsic factor, the method comprising: treating the fluid sample to free any vitamin B12 in the sample from endogenous intrinsic factor and to destroy the endogenous intrinsic factor's binding ability; combining the following with an amount of an immobilized primary antibody which specifically binds exogenous intrinsic factor: (a) an amount of exogenous intrinsic factor, (b) the treated fluid sample and (c) an amount of labelled vitamin B12 whereby the immobilized primary antibody binds all of the exogenous intrinsic factor, and any vitamin B12 in said sample and labeled vitamin B12 compete for reaction with the exogenous intrinsic factor; measuring the amount of labeled vitamin B12 bound to the primary antibody through the exogenous intrinsic factor; and using the measurement of the labeled vitamin B12 to determine the amount of vitamin B12 in the fluid sample.