Essentials for diagnosis 
1. Clinical manifestations  　
The disease is marked by slow onset, lassitude, hypodynamia, listlessness and declining appetite. Simple nephropathy occurs in younger children, mostly at the age of 2 to 7; nephritic nephropathy occurs in elder children, mostly at the age of above 7. The commonly-seen symptoms of simple nephropathy include high-degree pitting edema, in severe cases, even manifested as hydrothorax, ascites, hydrocele of tunica vaginalis and edema of scrotum which give rise to dyspnea, diarrhea or vomiting; edema occurs repeatedly, with occassional spontaneous relief. Edema of nephritic nephropathy is not as apparent as that of simple nephropathy. It may also be extremely mild, even unnoticeable, and the infantile patients have lustreless complexion, pale lips and whitish fur, hypodynamia with less activities, apathy and susceptibility to infection.

2. Laboratory examination

(1) Simple nephropathy  
Urinary protein excretion exceeds 0.1 g/kg per day; the serum albumin is lower than 30 g/L in children and 25 g/L in infants; plasma cholesterol exceeds 5.7mmol/L in children and 5.2mmol/L in infants.

(2) Nephritic nephropathy 
Besides the manifestations of simple nephropathy, it has one or more item (s) of the following four:
1) Marked hematuria., red blood cells in urine exceeds 10 cells/HP (seen in 3 times of centrifugal urine specimens within 2 weeks).

2) Hypertension lasts or occurs repeatedly (blood pressure in school-age children exceeds 17.3/12 kPa (130/90 mmHg) and 16.0/ 10.7 kPa (120/80 mmHg) in preschool-age children), the cases due to use of hormone are excluded in the above.
3) Persistent azotemia (blood urea nitrogen exceeds 10.7mmol/L, and the factor of hypovolemia is excluded)

4. Total blood complement volume (CH50) or blood C3 decreases repeatedly.