Diagnosis and Management of Lupus Nephritis

Initial Clinical Assessment

The American College of Rheumatology recommends that all patients with suspected lupus nephritis require kidney biopsy to confirm diagnosis, determine histologic class, and guide treatment decisions, as clinical and serologic findings alone are insufficient to establish the diagnosis or predict disease severity 1, 2
Baseline tests at initial evaluation should include renal function markers, such as serum creatinine, estimated GFR (eGFR), and serum albumin, as recommended by the European League Against Rheumatism 1
Urinalysis, including 24-hour urine collection for protein-creatinine ratio (PCR) and microscopic urinary sediment evaluation for red blood cells and casts, is essential for diagnosis and monitoring, according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 1, 2
Blood pressure measurement is crucial, as hypertension is both a manifestation and predictor of poor outcomes in lupus nephritis patients, as stated by the American Heart Association 1

Essential serologic markers include anti-dsDNA antibodies, which are positive in approximately 70% of lupus nephritis cases, and complement levels, such as C3 and C4, which indicate active disease and consumption, as recommended by the European League Against Rheumatism 3, 1
Anti-C1q antibodies are found in nearly 100% of patients with active lupus nephritis and have critical negative predictive value for flares, according to the Autoimmunity Reviews 3
Antiphospholipid antibodies should be measured at baseline to assess thrombotic risk and guide anticoagulation decisions, as stated by the American College of Rheumatology 1, 2

Kidney biopsy is mandatory for confirming lupus nephritis diagnosis, determining WHO/ISN-RPS histologic class, and assessing activity and chronicity indices, as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 1, 2
Indications for kidney biopsy include proteinuria >0.5 g/24 hours, active urinary sediment with red blood cells and/or casts, and rising serum creatinine without alternative explanation, according to the European Renal Association 1

The American College of Rheumatology recommends scheduling visits every 2-4 weeks for the first 2-4 months after diagnosis, then every 3-6 months lifelong, to monitor body weight, blood pressure, serum creatinine, eGFR, serum albumin, proteinuria, and urinary sediment 1
Serum C3, C4, and anti-dsDNA antibody levels should be monitored regularly, as well as complete blood count and lipid profile, according to the European League Against Rheumatism 1, 3