The Food and Drug Administration has approved a noninvasive test to determine whether a chronic kidney disease is caused by an autoimmune disease or another cause such as infection.
The EUROIMMUN Anti- PLA2R IFA blood test detects an antibody that is specific to primary membranous glomerulonephritis (pMGN). MGN, a chronic kidney disease, damages the glomeruli; it can lead to kidney failure and transplant. Symptoms include swelling, hypercholesterolemia, hypertension, and an increased predisposition to blood clots.
The condition mostly affects white men. It occurs in 2 of every 10,000 people and is more common after age 40, according to the National Library of Medicine. Risk factors include cancers, especially lung and colon cancer; exposure to toxins, including gold and mercury; infections, including hepatitis B, malaria, syphilis, and endocarditis; certain medications, including penicillamine, trimethadione, and skin-lightening creams; and systemic lupus erythematosus, rheumatoid arthritis, Graves’ disease, and other autoimmune disorders.
"Treatment of MGN depends on the underlying cause of the disease," said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health at the FDA’s Center for Devices and Radiological Health, in a statement. "This test can help patients get a timely diagnosis for their MGN and aid with earlier treatment."
Test manufacturer EUROIMMUN US submitted data that compared 275 blood samples from patients with presumed pMGN, with 285 samples from patients diagnosed with other kidney diseases including secondary MGN (sMGN) and autoimmune diseases. The test detected pMGN in 77% of the presumed pMGN samples, and gave a false-positive result in less than 1% of the other samples.
The diagnostic test helped distinguish pMGN from sMGN in most of the patients.
The FDA said that the test should not be used alone to diagnose pMGN, but that patients’ symptoms and other laboratory test results should also be considered. A kidney biopsy is required for confirmation, according to the FDA.
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