Abstract: An immunoassay making use of latex agglutination is practized by providing a colored latex as a latex, subjecting the colored latex to an immune reaction to form agglutinated particles of the colored latex, capturing the particles by means of a thin membrane with capillary-shaped pores formed therethrough, and then measuring the amount of the agglutinated particles thus captured.

Abstract: A component of a sample may be detected or quantitatively measured by an immunoreaction, namely causing a target substance-immunoreactive reagent labelled with a marker-reaction product and/or any remaining, unreacted, immunoreactive reagent to move while making use of capillarity, causing the reaction product or any remaining, unreacted, immunoreactive reagent to combine with a substance packed in a capillary tube, and is immobilized on a carrier and adapted to uptake labelled substance so as to immobilize the reaction product or any remaining, unreacted, immunoreactive reagent, and measuring the amount of the thus-immobilized labelled substance. Since reagents are all filled in the capillary tube, there is no such troublesome that the reagents have to be prepared and/or any extra reagents have to be discarded upon conducting the measurement. The immunoassay may be carried out at bed side in hospitals. An extremely small amount of the sample may be sufficient for its measurement.