Reference values of fetal serum β2-microglobulin in the Chinese: evaluation of its clinical usefulness.

Background: The level of β2-microglobulin was generally used to evaluate the renal function in adults. Elevated levels of β2-microglobulin were also applied to assess the perinatal situations in neonates and fetuses. The aim of our study was to establish and determine the reference values of fetal serum β2-microglobulin in the Chinese and to assess its clinical benefits in abnormal fetuses.

Methods: Data from 308 normal cord blood samples were obtained to calculate the normal reference values of fetal serum β2-microglobulin. According to the equations we obtained, we analyzed the level of β2-microglobulin in four case groups: renal malformation, hydrops, cytomegalovirus (CMV) infection and rubella virus (RV) infection.

Results: In the normal group, the concentration of β2-microglobulin decreased with the gestational age, with a mean value of 4.35±0.59 mg/L. The upper limit of β2-microglobulin was calculated as 7.55-0.074×gestational age in weeks. The levels of β2-microglobulin were significantly higher in the four case groups than the normal group. For the four groups, the sensitivity is 72.7%, 69.6%, 86.7% and 100%, respectively.

Conclusions: Fetal serum β2-microglobulin may be used as a predictor to evaluate the situations of fetal diseases.