Urinary aberrations in systemic lupus erythematosus not always indicative of lupus nephritis: a cross-sectional cohort study.

Our data confirm the importance of kidney biopsy for ruling out the presence of renal pathology other than LN. Patients with low-grade proteinuria may exhibit severe types of LN, which reinforces the need for early biopsies to detect LN. Key Points • Our findings show that histopathology changes other than lupus nephritis may occur in a significant number of patients with clinical and laboratory signs of novel kidney involvement. • Low-grade proteinuria does not exclude findings of active lupus nephritis that require the start of immunosuppressive therapy. • The study stresses the importance of performing kidney biopsies also in the presence of low-grade proteinuria or when signs of kidney function abnormalities occur. • This is crucial as early detection and prompt initiation of therapy may improve outcomes in lupus nephritis.