Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 10

State the significance of increased urinary 5-hydroxyindoleacetic acid.

Step 1 of 2

5-HIAA (5-hydroxyindoleacetic acid):

It is a degradation product of serotonin, which is excreted in urine in small volume.

• Serotonin is formed from tryptophan by the intestinal arginine cells, and carried by platelets throughout the body

• Generally, the body uses almost all serotonin, but when carcinoid tumors associated with argentaffin cell develops, serotonin is produced leading to high 5-HIAA in urine