Clinical utility of sperm DNA fragmentation testing: a commentary
The andrological factor is implicated in more than 40% of couples attending infertility clinics. Considering that standard semen analysis only poorly predicts the outcome of fertilization and pregnancy in couples including assisted reproduction attempts as it only examines sperm parameters such as sperm concentration, vitality, sperm morphology and motility, it is therefore quite limited in its clinical discriminatory power (1) in about 40% of men with normal ejaculates (2). Contributing factors to this fact are the high biological variability of these parameters, essentially causing each ejaculate being unique, thus often resulting in the vague clinical diagnosis of idiopathic infertility (3). In addition, the fertilization process itself is a multifactorial process in which not only the different sperm functions such as motility, capacitation, acrosome reaction, chromatin condensation or the integrity of the genetic information, but also female and oocyte factors have to be taken into account (4). Among these conventional sperm parameters, morphology evaluated according to strict criteria exhibited a relatively low degree of variability (4). Yet, although morphology appeared as a better parameter than sperm concentration, the diagnostic value of semen analysis is limited (5). For this reason, conventional semen analysis was complemented by a panel of functional sperm parameters including sperm nuclear DNA fragmentation, which is also regarded a parameter with low biological variation (6).