An enzyme immunoassay for neuron-specific enolase in cerebrospinal fluid.

A direct (as opposed to competitive) enzyme immunoassay (EIA) was developed to detect neuron-specific enolase (NSE) in cerebrospinal fluid (CSF). Most common methods of evaluating NSE levels have utilized radioimmunoassay. These are highly sensitive, but cannot be employed in laboratories not equipped or licensed for the use of radioisotopes. The EIA developed here shows sensitivity within the physiological range of values for CSF-NSE (> I ng/ml) and can be used in laboratories with appropriate densitometric scanning capabilities. The assay was applied to CSF samples obtained from patients with a variety of diagnoses at the time of surgical intervention for their respective disorders. While there were no diagnostically significant differences between the level of NSE in CSF from patients with different neurological disorders utilized in the development of this procedure, we were able to differentiate between marginally different levels of NSE. We conclude that we have developed a safe, fast, reliable, and sensitive assay for NSE in the CSF that can be used to study NSE levels in a variety of neurological cases.