1.Urine routine (1) Proteinuria Large amount of proteinuria is a necessary condition for nephrotic syndrome. (2) Urinary fibrinogen degradation product (FDP) Measurement of urinary FDP helps to classify glomerulopathy, and the measurement of urinary FDP for several times in a row, such as FDP <1.25?g/ml, the possibility of primary glomerulonephropathy (microscopic lesion nephropathy), and if the urinary FDP is persistently elevated, most of them are proliferative, membranous proliferation, or acute progressive crescentic nephritis. (3) Others: transparent tubular or granular tubular, hematuria (centrifugal urine erythrocytes >10/Hp) can be seen in nephritic nephropathy. Hypoalbuminemia: total plasma protein is reduced, albumin/globulin is inverted, plasma albumin is <30.0g/L, and <25.0g/L in infants. 3. Hyperlipidemia: Hypercholesterolemia and hypertriacylglycerolemia, blood cholesterol is ≥5.7mmol/L, and in infants ≥5.2mmol/L, and triacylglycerol is >1.2mmol/L. 4. Renal function: Generally normal, and urea nitrogen is mild in oliguria. Urea nitrogen is mildly elevated in oliguria. 5, protein electrophoresis α2-globulin increased significantly, γ-globulin decreased. 6, erythrocyte sedimentation rate erythrocyte sedimentation rate increased, persistent low complement blood, urine FDP in some nephritis can be greater than 1.25mg / L. 7, imaging examination Routine X-ray, ultrasound and electrocardiography. Chronic renal vein thrombosis can be found in X-ray examination, the affected kidney is enlarged, the ureter has a cut mark, ultrasound can sometimes be detected, if necessary, renal venography to confirm the diagnosis, in addition to the renal vein, other parts of the veins or arteries can also occur in this kind of comorbidity, such as femoral vein, femoral artery, pulmonary artery, mesenteric artery, coronary artery and intracranial arteries, etc., and cause the corresponding symptoms, the clinic choose to check the site and method according to the manifestation.