First of all, to introduce the premise of what kind of kidney biopsy is the test that needs to be taken? Kidney biopsy for histopathological examination is the most common diagnostic tool for kidney diseases. It is not only used for the pathological diagnosis of autologous kidney or transplanted kidney, but also helps to further understand the development and regression of the disease, and provides more information to guide the treatment and judge the prognosis. Advantages of renal biopsy: It is most valuable for understanding diffuse glomerular lesions. Where the clinical judgment is diffuse renal lesions and glomerulonephritis, nephrotic syndrome, asymptomatic proteinuria, asymptomatic hematuria, systemic lupus erythematosus, and polyarteritis nodosa are still in doubt in diagnosis, renal biopsy is the preferred diagnostic method. When drug-induced acute interstitial nephritis is clinically suspected but the etiology cannot be determined, renal biopsy can assist in diagnosis and guide treatment. In acute renal failure of unknown origin, renal biopsy can clarify the diagnosis, determine the treatment and judge the prognosis. If rejection occurs after kidney transplantation, kidney biopsy can determine whether the transplanted kidney should be removed. Kidney biopsy in patients with diabetes mellitus and hyperuricemia may help in the early diagnosis of diabetic nephropathy and uric acid nephropathy. The diagnosis of pulmonary hemorrhagic nephritis syndrome also depends on renal biopsy. Acute glomerulonephritis is not irreversible, and renal function can be significantly improved by performing timely renal biopsy and aggressive treatment after a clear diagnosis. The indications for kidney biopsy are: ① Consider diffuse lesions such as glomerulonephritis, nephrotic syndrome, systemic diseases such as systemic lupus erythematosus, diabetes mellitus, polyarteritis nodosa, amyloidosis, and other kidney damage. ②Unexplained hematuria, when non-glomerular source of hematuria is excluded, renal puncture biopsy should be performed to clarify the diagnosis. ③Unexplained and persistent proteinuria. ④Tubular-interstitial lesions are considered by clinical examination. ⑤ In cases of renal insufficiency, when there are difficulties in diagnosis and treatment plan, especially in acute onset and when acute nephritis is suspected, renal aspiration biopsy should be performed early to confirm the diagnosis and facilitate the development of treatment plan. (6) When chronic pyelonephritis is suspected, but chronic nephritis cannot be excluded, and there is insufficient clinical evidence for differential diagnosis. (7) If there is suspected rejection after kidney transplantation, or if the diagnosis of rejection is ineffective, or if there is a suspected recurrence of the original kidney disease, a kidney aspiration biopsy should be performed. (8) For other cases, such as unexplained hypertension, the condition and treatment require serial renal puncture biopsy to correct the diagnosis and revise the treatment plan. The procedure of percutaneous renal biopsy (1) Position: The patient is placed in a prone position with a 5- to l0-cm-high cotton pillow under the abdominal rib cage (equivalent to the position of the kidney area) to reduce kidney movement. Both upper limbs are placed on both sides and the head is tilted to one side. The patient is instructed to breathe calmly, and in special cases, the patient can be placed in the lateral position. (2) Skin disinfection: usually 1% povidone-iodine (iodophor) is used to disinfect the skin at least 2 times or more, including the upper to the subscapular line, the lower to the line of the posterior superior iliac spine, and the sides to the posterior axillary line, and then lay the towel. (3) Puncture point positioning: B ultrasound positioning (4) Local anesthesia: intradermal local anesthesia and subcutaneous local anesthesia along the route of needle entry, usually the syringe will cause negative pressure at the same time as the first needle, if there is no bleeding, while withdrawing the injection needle while injecting local anesthetic solution. (5) Puncture method: semi-automatic or fully automatic biopsy needle puncture for material. (6) Specimen length: the length of the kidney tissue taken is usually 10-15 mm. (7) Wound dressing: dressing for wound dressing after renal puncture, dressing with gauze and adhesive tape fixation.