Fetal serum α-1 microglobulin for renal function assessment: comparison with β2-microglobulin and cystatin C

To compare the prognostic value of fetal serum α1-microglobulin with that of β2-microglobulin and cystatin C for postnatal renal function.Retrospective study of α1-microglobulin, β2-microglobulin, and cystatin C in fetal serum from 126 fetuses with congenital abnormalities of the kidney and urinary tract (73 and 53, respectively). Two groups were defined: group with normal renal function and group with renal failure. For live born infants, renal function was assessed on the basis of serum creatinine (cutoff 50 µmol/L) or glomerular filtration rate (cutoff 75 mL/min/1.73 m2) or both. In case of infant or fetal death, histological kidney lesions were considered.Significant differences (p 0.001) were observed for the three markers between fetuses with good renal prognosis and those with renal failure (34.4 mg/L vs 67.6 mg/L for α1-microglobulin, respectively; 3.9 mg/L vs 7.35 mg/L, for β2-microglobulin, respectively; and 1.67 mg/L vs 2.12 mg/L for cystatin C, respectively). Areas under receiver operator curves were used to compare the three markers, 0.96, 0.90, and 0.74 for β2-microglobulin, α1-microglobulin, and cystatin C, respectively.Although α1-microglobulin is significantly different in fetuses with good renal prognosis and those with renal failure, overall, it is a less reliable prognostic marker than fetal serum β2-microglobulin.