Foetal serum but not urinary β2-microglobulin correlates with histological injury to the kidney

β2-microglobulin was measured in serum and/or urine from 27 foetuses with bilateral obstructive uropathy, and compared to the findings of kidney examination following the termination of pregnancy. In serum, increased β2-microglobulin levels correlated to a decreased number of glomeruli, a reduction in the blastema and the presence of primitive ducts reflecting renal hypoplasia and dysplasia. However, elevated β2-microglobulin levels in the urine correlated only to a decreased number of glomeruli.