The streptozyme antibody test (antistreptozyme [ASTZ]) is designed to measure antibodies against five streptococcal extracellular products: streptolysin O (SO), DNase B, hyaluronidase nicotinamide adenine dinucleotide glycohydrolase, and streptokinase, in a single test. A good correlation between ASO and ASTZ titers in sera of rheumatic fever patients has been demonstrated. However, no such comparison has been made in sera from other poststreptococcal sequelae. The evaluation of the streptozyme test in sera from 34 patients with streptococcal pyodermal nephritis was studied. Ninety seven percent of the patients developed high titers of antistreptozyme antibodies on the first bleeding after hospitalization, in contrast to only 40% of patients who developed elevated antistreptolysin O titers. The high antistreptozyme titers declined during convalescence and reached normal levels in the sixth month after onset of the disease. The most significant fall in titers occurred between 1 and 2 months from the onset of disease. The streptozyme test may be particularly helpful as a rapid screening test for antibodies in streptococcal pyodermal nephritis.