RESUMEN
The authors determined beta 2 microglobulin plasmatic and urinary levels in 35 children aged 1 month-14 years; 25 of them were suffering from reflux nephropathy. The results of this study indicate that B2 microglobulin concentrations in plasma and urine can be useful parameters to the clinical diagnosis and evaluation of severity of reflux nephropathy. In presence of reduced glomerular filtration rate B2 microglobulin plasmatic levels resulted significantly out of the normal range (mean = 3318; s.d. = 1184) and proportional to the residual functionality degree (p 0.005); blood B2 microglobulin values demonstrated a higher specificity (76.2%) than creatine clearance. Moreover Bt (B2 microglobulin urinary level), Bs (B2 microglobulin excretion per minute corrected to surface area) and Bf (B- microglobulin excretory fraction) were shown to vary (p 0.025) in relation to the presence and the degree of tubulo-interstitial damage. In particular, Bf values progressively impairing with the severity of the nephropathy, were shown to have a statistically good distribution and the best sensibility (95.2%) and specificity (77.8%) in detecting tubular damage.