Lateral flow, non-bibulous membrane assay protocols

An apparatus for measuring the presence or absence or approximate quantity of an analyte in a liquid sample which apparatus comprises, in combination:

• a non-bibulous lateral flow membrane;
• a housing for holding the membrane, said holding being so constructed as to form;
• means defining an application zone on the non-bibulous lateral flow membrane for receiving a liquid sample in said application zone;
• at least on indicator zone laterally apart from said application zone on said membrane to which is immobilized a member of a binding pair, said member being reactive with with analyte or a derivative or said analyte;
• and
• reading access means for permitting the indicator zone to be read, thus permitting measuring the presence or absence or approximate quantity of analyte by reading said indicator zone.

A method for determining the presence or approximate amount of analyte in a sample comprising the steps of:

• placing the sample on the liquid sample application zone of a non-bibulous lateral flow membrane which comprises a liquid sample application zone and at least one indicator zone spaced apart from said application zone laterally on the surface of said membrane, there being immobilized in said indicator zone a member of a binding pair capable of binding the analyte or a derivative thereof,
• said sample being of sufficient quantity to cause sample liquid to flow laterally from the application zone through said indicator zone to permit the binding of analyte or derivative thereof with the member of the binding pair immobilized in the indicator zone;
• and
• assessing the binding of the analyte or derivative thereof in the indicator zone, to determine the presence, absence or approximate amount of analyte.

A method for determining the presence or absence or approximate amount of an analyte in a liquid sample comprising the steps of:

• applying the sample to the liquid sample application zone of a non-bibulous lateral flow membrane having a pore size of 1-250 microns which membrane comprises said application zone and at least one indicator zone spaced laterally apart from said application zone on the surface of said membrane, there being immobilized in said indicator zone a member of a binding pair capable of binding the analyte or a derivative thereof,
• said sample being of sufficient quantity to cause sample liquid to flow laterally from the application zone through said indicator zone;
• and
• detecting the binding of the analyte or derivative thereof in the indicator zone;
• wherein said detecting is effected by entrapping detectable particles in a complex formed by the binding of the analyte or derivative thereof with the member of the binding pair immobilized in the indicator zone;
• and
• assessing the entrapment of the particles in the indicator zone to determine the presence or absence of approximate amount of analyte.

A method of type blood, which method comprises applying a sample of whole blood to the liquid sample application zone of a non-bibulous lateral flow membrane, wherein the membrane comprises:

• said application zone defined to receive said whole blood sample, and
• at least one indicator zone spaced laterally apart from the application zone, said indicator zone having immobilized therein an antibody or fragment thereof immunoreactive with a blood typing antigen,
• said whole blood sample being of sufficient volume to permit the whole blood to flow through the indicator zone, and
• applying sufficient clear liquid to the membrane at a position apart from the indicator zone so as to laterally flow through the indicator zone to remove unbound reed blood cells from said indicator zone and
• detecting the presence or absence of red color in the indicator zone so as to determine the presence or absence of a blood typing antigen immunoreactive with the antibody or fragment thereof immobilized in the indicator zone.