Immunochromatographic method and device.

摘要

A method for determining the presence of an analyte in a sample suspected of containing the analyte is disclosed. The analyte is a member of a specific binding pair ("sbp member") consisting of ligand and its complementary receptor. The method comprises contacting, with a test solution containing said sample and a first sbp member analogous to said analyte, a contact portion of a piece of bibulous material capable of being traversed in at least one direction by said test solution by capillary migration. The bibulous material contains a second sbp member capable of binding the analyte and the first sbp member. The second sbp member is non-diffusively bound to the bibulous material at least at a portion thereof between the contact portion and a small situs on the piece separated from the contact portion. The surface area of the situs is substantially less than that of the piece of bibulous material. the situs is capable of binding the first sbp member not bound to said second sbp member. Next, at least a portion of the test solution is allowed to traverse the bibulous material by means of capillary migration and thereby contact the situs. The situs is examined for the presence of the first sbp member at the situs, which is usually indicated by the presence of a detectible signal. Such signal can be directly detectible, or the situs can be exposed to a signal producing means capable of interacting with the first sbp member to produce a detectible signal at the situs in relation to the amount of analyte in the sample. The signal at the situs is distinguishable from signal detectible at portions of the bibulous material other than the situs.