Interferences caused by bilirubin, hemolysis, and lipemia on 25 clinical chemistry analytes in bovine, canine, equine, and feline sera were studied using the Coulter Dacos and commercial reagents. We present the data as "interferograms", which show the anticipated percent change in serum analyte activity or concentration with varying concentrations of bilirubin, hemoglobin, or lipid. Obvious species differences in response to at least one added interfering substance were found for alanine aminotransferase, aspartate aminotransferase, cholesterol, creatine kinase, globulin, total protein, and urea. The remaining analytes were affected in a linear or complex dose-response relationship or were only affected at the highest concentrations of interfering substances. These data will be useful in aiding interpretation of laboratory test results when common interferences are present in the serum.