For the purpose of these recommendations, lupus nephritis is defined as clinical and laboratory manifestations that meet ACR criteria (persistent proteinuria > 0.5 g per day or greater than 3+ by dipstick, and/or cellular casts including red cell, hemoglobin, granular, tubular or mixed) [12 (link)]. A review of the ACR criteria has recommended that a spot urine creatinine/protein ratio >0.5 can be substituted for the 24 hour protein measurement, and “active urinary sediment” (>5 RBC/hpf, >5 WBC/hpf in the absence of infection, or cellular casts limited to RBC or WBC casts) can be substituted for cellular casts [1 (link)]. An additional, perhaps optimal, criterion is a renal biopsy demonstrating immune complex-mediated glomerulonephritis compatible with lupus nephritis [1 (link)]. Finally, for the purpose of implementing these recommendations, the Core Executive Panel felt that a diagnosis of lupus nephritis should also be considered valid if based on the opinion of a rheumatologist or nephrologist.