1, nephrotic syndrome relapse: refers to 3 consecutive days, morning urine protein from negative to 3+ or 4+, or 24-hour urine protein quantification ≥ 50mg/kg. 2, nephrotic syndrome frequent relapse: refers to ≥ 2 relapses within 6 months or ≥ 3 relapses within 1 year in the course of nephrotic disease.