How Is Lupus Nephritis Diagnosed?

A diagnosis of lupus nephritis is usually made by a nephrologist or a rheumatologist and generally requires a kidney biopsy. Up to one-third of people with Systemic Lupus Erythematosus (SLE) develop lupus nephritis within 15 years of diagnosis. 

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. Your physician will check your urine for protein and other substances needed to determine how well your kidneys are working. Too much protein in the urine is also 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 or another medical specialist, such as a radiologist, may perform a kidney 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 looked at under a microscope to determine how much inflammation or scarring is present. Your nephrologist or rheumatologist will use the results of your kidney biopsy to categorize or stage your lupus nephritis. For more information about what happens during a kidney biopsy, visit the National Kidney Foundation website.

Hope after Diagnosis

Obtaining a diagnosis of lupus nephritis can be scary and confusing. You may feel so troubled by the diagnosis that you leave your doctor's office without asking important questions. Or you may have been given so much information by your doctor that you can't remember it all. That's why you may want to bring a trusted friend or family member with you during doctors' visits — someone who can jot down important information, ask questions of your physician, and provide moral support.

Another helpful tip: print out the Guide to Talking with Your Doctor, and bring it with you on follow-up visits to help you organize your thoughts and get your questions answered. Although being diagnosed with lupus nephritis can be very emotional, know that early diagnosis and treatment may improve long-term results.

Early Diagnosis and Treatment of lupus nephritis may improve long-term results

Guide to Talking with Your Doctor

Make the most of your healthcare appointments. Download this helpful discussion guide and bring it with you to your next doctor's visit.

Download Guide

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