Diagnosis of Lupus Nephritis
A diagnosis of lupus nephritis is usually made by a Nephrologist or a Rheumatologist. A Nephrologist will confirm the diagnosis through a kidney biopsy. Up to one-third of people with Systemic Lupus Erythematosus (SLE) develop lupus nephritis within 15 years of diagnosis. One in 5 people with lupus nephritis are believed to be undiagnosed.

The three most common tests used to diagnose lupus nephritis are: a urine test, blood test, and a kidney biopsy. Each test for lupus nephritis is explained in more detail below.

Urine Test
Because there are so few symptoms of kidney disease, and because significant kidney damage can happen before you are even diagnosed, testing your urine is necessary to uncover any problems with the way your kidneys are functioning.

During a urine test, or urinalysis, a sample of your urine is collected in your healthcare provider's office and usually sent to a laboratory for analysis. A dipstick placed in the urine will change color if blood or protein is present. A high number of red blood cells or too much protein in the urine indicate kidney damage. Too much protein in the urine is referred to as proteinuria.

Blood Test
A blood test can also provide information about kidney damage and how well your kidneys are functioning. A blood test measures creatinine, a waste product that results from the normal breakdown of muscles in your body. Your kidneys naturally remove creatinine from your blood. The amount of creatinine in your blood is used to estimate your glomerular filtration rate (GFR). GFR is a calculation that determines how well your blood is filtered by your kidneys. As kidney (renal) disease gets worse, the level of creatinine goes up.

Kidney Biopsy
To confirm a diagnosis of lupus nephritis, your nephrologist will perform a kidney (renal) biopsy. The biopsy, which is typically an outpatient procedure performed in a hospital, involves taking a small piece of kidney tissue and examining it under a microscope. During the procedure, you lie on your stomach while your nephrologist inserts a thin, long needle through the skin of your back and removes a tiny piece of tissue from one of your kidneys. The tissue is viewed under a microscope to determine how much inflammation or scarring is present. For more information about what happens during a kidney biopsy.