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

OBJECTIVE

To compare the prognostic value of fetal serum α1-microglobulin with that of β2-microglobulin and cystatin C for postnatal renal function.

METHOD: 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.

RESULTS

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.

CONCLUSION

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.