What do Semen Parameters Mean? How to Define a Normal Semen Analysis

Although abnormal semen parameters are generally considered to be poor predictors of fertility, Semen Analysis (SA) parameters are often used as a screening test to detect male factor infertility. Certainly, men with azoospermia or severe oligozoospermia have markedly impaired fertility potential [1-3]. Since men with abnormal fertility could undergo various medical or surgical treatments to improve semen parameters and fertility, it is clinically relevant to have a test for infertility. According to the American Society for Reproductive Medicine and American Urological Association guidelines, semen analysis and male reproductive history are considered the primary screening evaluation for male fertility potential [3,4]. So, published guidelines for normal semen parameters have substantial clinical relevance. The World Health Organization (WHO) published an updated 5th edition of their reference values for human semen characteristics in 2010 [5,6]. This version presented substantially different numbers for the definition of abnormal semen parameters when compared to prior manuals. Application of these new reference values would result in reclassifying a substantial number of men as not having male factor infertility, and limit couples’ fertility options. Controversy over the changes is heated; some andrology laboratories have elected to ignore the new reference semen parameter values, and instead apply older standards or even arbitrary SA reference values because of concerns about the validity of these numbers [7].