A colorimetric testing device and method

摘要

A colorimetric indicator testing device to determine the presence of a minute amount of a specific substance in a liquid medium is in the form of a test card (12) which includes top and bottom sheets (14,24) adhesively secured to an intermediate frame member (18) which, together with the top and bottom sheets, defines a filter chamber housing a flat filter (30). A test portion of the filter has on it a binding substrate to which antibodies of the specific substance have been bound. This binding substrate is in communication with a test port (40) through which there is administered a substance to be tested which contains an unknown amount of antigen. After the sample is administered an aqueous solution of enzyme labelled antigen is administered and, subsequently, a liquid substrate is added to cause a color change in the filter (30) below the test port (40), inversely proportional to the amount of antigen contained in the sample. A control port 42 may receive reagents only.