The present invention provides isolated monoclonal antibodies that selectively bind albumin from animals. Also provided are methods using such antibodies for the detection of early renal disease in animals. The method includes the steps of (a) obtaining a sample from an animal to be tested; (b) contacting the sample with an antibody having a greater avidity for feline albumin than for other proteins or components in the sample; (c) detecting the complex formed by the antibody and albumin; and (d) determining the amount of albumin in the sample from the amount of antibody-albumin complex detected. An amount of albumin in the range of from 10 .mu.g/ml to about 300 .mu.g/ml indicates the presence of early renal disease.