Test device

A test strip for quantitatively determining the ligand binding capacity of a liquid sample which comprises:

• a length of strip characterized by
• a length of capillarity having a first and second end therealong,
• a first zone located in said length of capillarity and spaced from said first end of the capillarity to permit contact of said first end but not said first zone with a developing liquid and impregnated with a first reagent,
• said reagent being chosen to be mixable with said ingredient to provide a label therefor, and
• a second zone located in said length of capillarity in the direction of said second end from said first zone and including a second reagent adapted to slow capillary movement of a portion of said first reagent carried by said developing liquid,
• said length of capillarity being chosen to stop capillary transport therethrough while said portion of said first reagent is in said second zone,
• whereby a sample may be received in said length of capillarity and spaced from said first end of said capillarity to permit contact of said first end but not the place of sample reception with the developing liquid, said place of sample reception being in said length of capillarity between said first end and said second zone,
• and wherein said first reagent includes a labeled form of said ligand, said ligand existing in a free form and a bound form, said second reagent includes a binding agent capable of binding said labeled form of said ligand when in one of said free form and said bound form but not when in the other, said labeled form and said binding agent being incorporated with said strip in their respective zones in predetermined quantities such that an amount of a measurable characteristic of said labeled form results at a predetermined location on said strip upon traversal thereof by said developing liquid from said first end to said second end, which quantity of said measurable characteristic is a function of the ligand binding capacity of said liquid sample.