When clinical clues suggest IgA nephropathy, the scale of grasp of indications for renal puncture biopsy varies from country to country and from scholar to scholar. In foreign countries, active renal puncture is generally not advocated for patients with asymptomatic hematuria; therefore, the international KDIGO guidelines recommend that patients with glomerular hematuria need regular review and monitoring of blood pressure, proteinuria and renal function at regular intervals; however, some scholars believe that patients with definite glomerular hematuria should be mobilized for renal puncture as long as there are no contraindications, because, certain etiologies (e.g., thin basement membrane nephropathy) caused by hematuria do not require treatment at all. It is generally accepted that in patients with clinically indicated IgA nephropathy, renal puncture biopsy is of greater significance in the following cases: 1. 24-hour urine protein quantification greater than 1 gram; 2. elevation of blood creatinine at the onset of disease; 3. hematuria significantly accompanied by short-term elevation of blood creatinine; 4. hematuria with hypertension; 5. glomerular disease suspected to be secondary to systemic disease; 6. suspected combination of other glomerular diseases. Some scholars believe that if renal biopsy is performed according to the criterion of 24-hour proteinuria greater than 1 gram, it may miss some patients who need active treatment, such as some patients with 24-hour urine protein around 0.5 grams, but the renal pathology shows moderate (Lee classification) damage. Biopsy.