Renal biopsy is required in the following cases: 1. Nephrotic syndrome: When the etiology of nephrotic syndrome is unknown, consider whether it is secondary to systemic disease. 2, glomerulonephritis with rapid renal decompensation, kidney biopsy is required to determine the pathological type of their renal damage. 3. In acute nephritis syndrome, renal biopsy can reveal the morphology of inflammation and immune deposits and their extent, which is important for the early diagnosis and treatment of acute nephritis. Primary acute nephritis with atypical clinical manifestations or acute nephritis that does not heal after several months or decreased renal function. 4, primary nephrotic syndrome seen in adults is best to do a kidney biopsy to determine its tissue type before using hormones to avoid side effects caused by the blind use of hormones, especially for those who are ineffective in treatment. 5, patients with hematuria can consider kidney biopsy if the diagnosis is not established after various tests have excluded non-glomerular hematuria, and kidney biopsy should be done for persistent hematuria without clinical manifestations and for hematuria with proteinuria and 24-hour urine protein quantification greater than 1 gram. 6.For those who have proteinuria for a long time without any symptoms, kidney biopsy can clarify the pathological type to facilitate the use of drugs and prognosis. 7. Lupus nephritis, renal hypertension, acute renal failure and chronic renal failure of unknown origin can be diagnosed by kidney biopsy to help diagnosis. When the above situation occurs, patients had better go to the hospital for kidney biopsy to make a clear diagnosis. The significance of kidney biopsy: Understanding the histomorphological changes of the kidney provides an important basis for clinicians to judge the condition, treat the disease and estimate the prognosis. It can be said that the development of renal pathology examination is a leap forward in the development of nephrology. At present, the results of renal pathology examination have become the golden indicator for the diagnosis of kidney diseases. To summarize, the clinical significance of renal puncture examination is mainly as follows: (1) Clear diagnosis: the clinical diagnosis of more than one third of patients can be revised through renal puncture biopsy. (2) Guidance of treatment: The clinical treatment plan of nearly one third of patients can be modified by renal puncture biopsy. (3) Estimation of prognosis: The prognosis of patients with kidney disease can be more accurately evaluated by renal puncture biopsy. In addition, repeat renal pathology is sometimes required to understand the effectiveness of treatment or to understand the progression of pathology (e.g., crescentic nephritis, lupus nephritis, and IgA nephropathy).