Reference values of amniotic fluid neuron-specific enolase.

Objective : Enolase is a dimeric cytoplasmic enzyme whose double n isoenzyme, neuron-specific enolase, is predominantly found in neuronal and neuroendocrine tissues. Cell injury causes its release into the blood and cerebrospinal fluid (CSF). Neuron-specific enolase has been measured in the serum and CSF of adults and full-term asphyxiated neonates as a marker of neurological injury. We recently observed an elevation of neuron-specific enolase in the amniotic fluid of women whose neonates subsequently developed intraventricular hemorrhage or periventricular leukomalacia. The purpose of our study was to establish reference values of neuron-specific enolase in the amniotic fluid as a function of gestational age. Methods : A total of 110 amniotic fluid samples, obtained primarily for genetic studies (16-20 weeks, n = 22), for evaluation of preterm labor (21-35 weeks, n = 66) and for fetal lung maturity studies (36-40 weeks, n = 22), were analyzed for neuron-specific enolase. Samples were from women who s...