Neuron Specific Enolase (NSE) test is conducted to detect small cell lung carcinoma, neuroendocrine tumors, cough, breathing problems, weakness and rapid weight loss. This test also determines the level of neuro-specific enolase in the blood serum only. This test is generally performed as a follow-up marker for the patients who are having tumors that secrete NSE. Neuro specific enolase test is conducted using a blood sample. If the patient is undergoing treatment then slowly NSE levels should be decreased, but in case if they are increasing rapidly then it is considered as tumor still exists and is spreading slowly.