Purpose
Azoospermia is defined as the absence of spermatozoa in the pellet of a centrifuged semen sample. In fact, when a basic semen analysis fails to detect sperm in the ejaculate, there is still the possibility of detecting rare sperm after centrifugation of the sample and examination of the pellet. In this study, we assessed the role of Cytospin centrifugation in combination with the nuclear fast picroindigocarmine (NF-PIC) staining in identifying sperm in azoospermic samples.

Materials and Methods
Semen samples of 251 men diagnosed as having azoospermia after standard examination were further analyzed by Cytospin centrifugation in combination with NF-PIC staining.

Results
Sperm were detected in 60 men (23.9%), thus changing their diagnosis to cryptozoospermia.

Conclusions
By identifying sperm in the semen of men who were thought to have total azoospermia, the Cytospin NF-PIC test can alter the diagnosis and further treatment of these men.