means absence of sperm in the semen.fructose levels should be determined in any patient with azoospermia. especially in those whose ejaculate volume is less than 1 ml, suggesting seminal vesicle
obstruction . Absence of fructose, low semen volume, and failure of the semen to coagulate indicate either congenital absence of the vas deferens and seminal vesicles or obstruction of the ejaculatory duct
.Normal levels is13 micrmole or more per ejaculate.