Tests and diagnosis

By Mayo Clinic Staff

The main sign of membranous nephropathy is the loss of protein, primarily albumin, from the blood into the urine (proteinuria). An otherwise healthy person would excrete less than 50 milligrams (one-thousandth of an ounce) of albumin a day in the urine. Someone with membranous nephropathy may excrete several hundred milligrams of albumin a day, up to more than 10 grams (four-tenths of an ounce) with advanced disease.

Tests used to determine the cause of the disease and how well your kidneys are functioning include:

  • Urine tests to determine the amount of protein in the urine — urine creatinine estimates the concentration of your urine
  • Glomerular filtration rate (GFR), which tells how much kidney function you have
  • Cholesterol and triglyceride (lipids) levels in your blood
  • Fasting blood sugar and glycosylated hemoglobin tests for diabetes
  • An antinuclear antibody test for collagen vascular disease
  • Screening blood tests for autoimmune diseases
  • Tests for hepatitis B and C
  • Ultrasound or CT scans to examine the structure of your kidneys and urinary tract

Removing a small piece of your kidney tissue for a pathologist to examine under a microscope (kidney biopsy) is the best way to identify the kind of kidney disease, to see how much damage has occurred and to evaluate the effectiveness of treatment.

Oct. 12, 2011