Abstract: The invention provides an assay method for determining a level of haptoglobin in a sample comprising the steps of: (i) mixing haemoglobin with the sample to be assayed so as to form a haptoglobin-haemoglobin complex with haptoglobin present in the sample; (ii) contacting the product of step (i) with reagents for generating hydrogen peroxide and one or more chromogens which undergo a spectroscopically detectable change when peroxidase activity is present, in the presence of a buffer, under conditions in which hydrogen peroxide is generated from said reagents and forms a substrate for the peroxidise activity of the haptoglobin-haemoglobin complex present, and wherein the pH of the buffer is within a range which is sufficiently low that the peroxidise activity of any uncomplexed haemoglobin is substantially suppressed but sufficiently high that hydrogen peroxide generation occurs; (iii) determining the peroxidase activity of the haptoglobin-haemoglobin complex by measuring the change in an optical property of th

Abstract: An assay for the detection of haptoglobin (Hp) in milk using an Hp-specific antibody as a means to predict or detect mastitis or subclinical mastitis by way of Hp being an associated marker and/or to test the quality of milk, in, for example, dairy cattle.

Abstract: The present invention relates to a haptoglobin assay of the type wherein the level of haptoglobin in a sample to be tested is determined by measuring the peroxidase activity of haptoglobin/haemoglobin complex. The assay employs at least one reagent for reducing a peroxidase effect due to any albumin or any other protein(s) present in the sample. The reagent may be selected from a) a reducing agent effective against disulphide bonds; b) a protein binding inhibitor and/or c) a chaotropic agent. The present invention also relates to kits suitable for use in such an asay.