Protein composition of urinary casts from healthy subjects and patients with glomerulonephritis.

Urinary casts from 46 healthy volunteers and 60 patients with glomerulonephritis were examined for the presence of Tamm-Horsfall glycoprotein and other proteins. All samples gave immunofluorescence evidence of Tamm-Horsfall protein in casts. Casts from 59 of the patients but only three of the controls contained other proteins in addition (p less than 0.001). Immunoglobulins (IgG, IgM, IgA) were detected in casts from 53 of the patients but none of the healthy volunteers. Examination of urinary casts for immunoglobulins, complement, and fibrin provides a non-invasive method for distinguishing patients with active glomerular disease.