Method for immunochromatographic analysis

Methods are disclosed for conducting assays. One such method comprises providing in combination a first bibulous member zone ("first zone") and a liquid medium containing a component. The first zone has non-diffusively bound thereto a reagent interreactive with the component. Conditions are selected wherein the liquid medium and at least a portion of the component contained therein traverse all of the first zone and migrate into a second bibulous member zone ("second zone") of a different composition than the first zone by capillary migration. The distance the component has migrated into the second zone or the difference in the distances the medium and the component have migrated into the second zone is determined, the distance or the difference being related to the amount of the component in the liquid medium or the amount of the reagent. Another such method comprises causing a specific binding pair member in a first liquid medium to become bound to a first bibulous member by contacting a portion of the first bibulous member with the medium. The first bibulous member is in liquid receiving relationship with an absorbent member. The contacting is carried out under conditions wherein the first medium traverses the first bibulous member and at least a portion of the absorbent member by capillary action. The method further comprises causing the first bibulous member to come into liquid receiving relationship with a second bibulous member. A component in a second liquid medium is transported to and preferably becomes non-diffusively bound to the second bibulous member in relation to the presence of analyte in the first medium. This is accomplished by contacting a portion of the first bibulous member with the second medium under conditions wherein the second medium traverses the first bibulous member by capillary action and at least a portion of the second bibulous member. Next, the presence of the component on at least a portion of the second bibulous member is determined.