There have been numerous researches on urine β₂-microglobulin (β₂-M) concerned with primary nephrotic syndrome and other glomerular diseases, but not much has been done in relation to pediatric age groups. Thus, our hospital decided to study the relations between the analysis of the test results we have conducted on pediatric patients and renal functions.

Retrospective data analysis was done to 102 patients of ages 0 to 4 with renal diseases with symptoms such as hematuria, edema, and proteinuria who were admitted to Chung-Ang Yongsan Hospital and who participated in 24-hour urine and urine β₂-M excretion test between January of 2003 and January of 2006. Each disease was differentiated as independent variables, and the statistical difference of the results of urine β₂-M excretion of several groups of renal diseases was analyzed with student T-test by using test results as dependent variables.

Levels of urine β₂-M excretion of the 102 patients were as follows : 52 had primary nephrotic syndrome [MCNS (n=45, 72±45 µg/g creatinine, µg/g-Cr), MPGN (n=3, 154±415 µg/g-Cr), FSGS (n=4, 188±46 µg/-Cr)], six had APSGN (93±404 µg/g-Cr), seven had IgA nephropathy (3,414±106 µg/g-Cr), 9 had APN (742±160 µg/g-Cr), 16 had cystitis (179±168 µg/g-Cr), and 12 had HSP nephritis (109±898 µg/g-Cr). IgA nephropathy ( P <0.05) and APN ( P <0.05) were significantly higher than in other renal diseases. Among primary nephrotic syndrome, FSGS with higher results of β₂-microglobulin test had longer treatment period ( P <0.01) when compared to the lower groups, but no significant differences in Ccr, BUN, or Cr were observed.

IgA nephropathy and APN groups showed significantly higher level of β₂-M excretion value than other groups. Although β₂-microglobulin value is not appropriate as an indicator of general renal function and pathology, it seems to be sufficient in the differential diagnosis of the UTI and in the prediction of the treat-ment period of nephrotic syndrome patients.