Test device and method for colored particle immunoassay

A method for determining the presence of an analyte in a liquid sample comprising:

• a) adding a liquid sample to a first portion of a test device comprising
• a permeable material defining at least a first portion and a second portion, the portions being in the same plane so as to permit capillary flow communication with each other
• said first portion being the site for application of the liquid sample, and for a conjugate movably supported therein, wherein said conjugate consists of a binder for the analyte coupled to a colored particle, and
• said second portion being the site for visually determining the presence of the colored particle, said second portion consisting of a binder immobilized therein which specifically binds to the analyte;
• b) allowing the liquid sample to flow to the second portion of the permeable material;
• and
• c) determining the presence of the analyte in the liquid sample by visual inspection of the second portion for color development, wherein the presence of the analyte is indicated by the presence of the colored particles.

A method for determining the presence of an analyte in a liquid sample comprising:

• a) adding a liquid sample to a first portion of a test device comprising
• a permeable material defining at least a first portion and a second portion, the portions being positioned so as to permit capillary flow communication with each other
• said first portion being the site for application of the liquid sample, and for a conjugate movably supported therein, wherein said conjugate consists of a binder for the analyte coupled to a colored particle, and
• said second portion being the site for visually determining the presence of the colored particle, said second portion consisting of a binder immobilized therein which specifically binds to the analyte;
• b) allowing the liquid sample to flow to the second portion of the permeable material;
• and
• c) determining the presence of the analyte in the liquid sample by visual inspection of the second portion for color development, wherein the presence of the analyte is indicated by the presence of the colored particles.

A test device comprising a conjugate and a test strip;

• the conjugate comprising a first binder for a ligand and a colored particle bound thereto, the conjugate forming a complex with the ligand when present together in liquid;
• the test strip comprising a sorbent material defining a flow path extending from a sample application site to at least a test site, the flow path guiding therealong transport of the conjugate and a liquid suspected to contain a ligand;
• a second binder for capturing the ligand or the complex, the second binder being immobilized at the test site;
• whereby accumulation of colored particles at the test site produces a color visible to the unaided eye indicative of the presence of the ligand in the liquid.

A method of detecting a ligand in a liquid sample, the method comprising the steps of:

• (a) providing a test device comprising a conjugate and a test strip,
• the conjugate comprising a first binder for a ligand and a colored particle bound thereto,
• the test strip comprising a sorbent material defining a flow path extending from a sample application site to at least a test site,
• a second binder for capturing the ligand or the complex, the second binder being immobilized at the test site;
• (b) applying a liquid sample to the device upstream of the test site so that
• the sample and the conjugate are transported to the test site by liquid wicking or wetting along the flow path, and the conjugate forms a complex with the ligand when present together in the liquid;
• and
• (c) observing visually the test result at the test site wherein the accumulation of colored particles produces a color indicative of the presence of the ligand in the liquid.

A test device comprising a conjugate and a test strip:

• the conjugate comprising a ligand or an analog thereof and a colored particle bound thereto;
• the test strip comprising a sorbent material defining a flow path extending from a sample application site to at least a test site, the flow path guiding transport therealong of the conjugate and of a liquid suspected to contain a ligand;
• a binder for capturing the ligand and the conjugate competitively, the binder being immobilized at the test site;
• whereby accumulation of colored particles at the test site produces a color visible to the unaided eye indicative of the absence of a detectable level of the ligand in the liquid.

A method of detecting a ligand in a liquid sample, the method comprising the steps of:

• (a) providing a test device comprising a conjugate and a test strip,
• the conjugate comprising a ligand or analog thereof and a colored particle bound thereto,
• the test strip comprising a sorbent material defining a flow path extending from a sample application site to at least a test site,
• a binder for capturing competitively the ligand and the conjugate, the binder being immobilized at the test site;
• (b) applying a liquid sample to the device upstream of the test site so that
• the sample and the conjugate are transported to the test site by liquid wicking or wetting along the flow path;
• and
• (c) observing visually the test result at the test site wherein the accumulation of colored particles produces a color indicative of the absence of a detectable level of the ligand in the liquid.