Abstract: The present invention relates to a method for measuring heptoglobin level in blood serum by using antibodies for ? and ? subunits of heptoglobin, and a kit for immunodetection of heptoglobin which comprises the antibodies for ? and ? subunits of heptoglobin for measuring heptoglobin level in blood serum. A method for measuring heptoglobin level in blood serum of the present invention comprises the steps of: reacting blood serum of a subject with an antibody (?h antibody) which binds specifically to ? subunit of a dimeric heptoglobin and an antibody (?h antibody) which binds specifically to ? subunit of a dimeric heptoglobin; and, measuring level of proteins which react with the ?h antibody and ?h antibody in blood serum and have a molecular weight of more than 100 kDa.