September/2006

ANSWER 1 =B

DISCUSSION:

Carcinoid tumors are classified as biochemically typical or atypical based on the presence of high levels of serotonin in so-called typical tumors.The best-known metabolite of serotonin in carcinoid tumors is 5-HIAA. In a 24-hour sample, the urinary level of 5-HIAA is the test most commonly used in the endocrine work-up of carcinoid tumors.