It is usually not possible to determine the stage of nephropathy based on purpura nephritis grade 3a alone. The stage of nephropathy usually needs to be judged according to the glomerular filtration rate. The lesions of purpura nephritis grade 3a are mainly manifested as mesangial proliferative nephritis with less than 50% crescent formation or segmental lesions or thrombosis, necrosis, sclerosis, and grade 3a is mainly focal. Clinically, laboratory data such as urea and creatinine are commonly used to derive glomerular filtration rate from various formulas in combination with information about the patient’s sex, age, and ethnicity. Therefore, it is necessary to improve the urea nitrogen, creatinine and other related renal function tests to calculate the glomerular filtration rate to stage the nephropathy. It is usually impossible to determine the stage of nephropathy based on pathological grading alone. Patients with purpura nephritis grade 3a are advised to go to regular hospitals in time and receive standardized treatment under the guidance of doctors.