An object of the present invention is to provide a blood test kit and a blood analysis method, which are for performing quantitative analysis of components by precisely obtaining a dilution factor. According to the present invention, provided is a blood test kit for analyzing a concentration of a target component in a blood sample using a normal component which is homeostatically present in blood, the kit including a diluent solution for diluting the blood sample, a first storing instrument for storing the diluent solution, a separation instrument for separating and recovering blood plasma from the blood sample diluted with the diluent solution, a holding instrument for holding the separation instrument, a second storing instrument for storing the recovered blood plasma, and a sealing instrument for keeping the stored blood plasma within the second storing instrument, in which the separation instrument is composed of glass fiber coated with a resin.