An easy, reproducible and cost-effective method for andrologists to improve the laboratory diagnosis of nonobstructive azoospermia: a novel microcentrifugation technique

Abstract

This study describes a new method of microcentrifugation as an improved, viable, cost-effective option to the classical Cytospin apparatus to confirm azoospermia. Azoospermic semen samples were evaluated for cryptozoospermia by a centrifugation method similar to that of World Health Organization guidelines (2010; entire specimen centrifuged at 3000g for 15 min, and aliquots of the pellet examined). Then, if no sperm were detected, the pellet from that procedure was resuspended in culture medium, centrifuged (2000g for 15 min), and the entire pellet spread on a 4 X 6mm area of a slide and stained using the Christmas tree method (Nuclear-Fast solution and picric acid). The entire stained area was examined for the presence or absence of sperm. A total of 148 azoospermic samples (after standard WHO diagnosis) were included in the study and 21 samples (14.2%) were identified as sperm-positive. In all microcentrifugation slides, intact spermatozoa could be easily visualized against a clear background, with no cellular debris. This novel microcentrifugation technique is clearly a simple and effective method, with lower cost, increasing both sensitivity and specificity in confirming the absence or presence of spermatozoa in the ejaculate. It may represent a step forward of prognostic value to be introduced by andrology laboratories in the routine evaluation of patients with azoospermia in the initial semen analysis.

Figure 1. Spermatozoa found after microcentrifugation technique (2000g for 15 minutes), stained by nuclear fast red and picroindigocarmine (described as NF-PICS or Christmas Tree stain) in an azoospermic man. We observed clear slides obtained with sperm integrity preserved, without cellular debris.