This kit is used for quantitative detection of NSE in human serum in vitro. Neuron specific enolase (NSE) is a tumor marker for detecting small cell lung cancer (SCLC). SCLC is sensitive to combined chemotherapy and radiotherapy. The concentration of NSE in serum will be reduced to normal level in most cases. However, most of the patients with SCLC will still recur. The recurrence of SCLC can be predicted before 4-12 weeks by monitoring the treatment process with NSE concentration, which is obviously earlier and more convenient than the chest X-ray examination. Therefore, the level of serum NSE has practical significance in the diagnosis, differentiation, condition judgment and efficacy evaluation of SCLC.