Comparison between WHO (World Health Organization) 2010 and WHO 1999 parameters for semen analysis – interpretation of 529 consecutive samples

Objective: To quantify how many men with normal semen according to WHO (WHO - World Health Organization) 1999 criteria, should be considered with abnormal semen according to 2010 criteria and vice versa; to study which parameter of volume, concentration, motility and morphology is the most responsible of this change. Materials and methods: We studied, using WHO 1999 parameters, 529 consecutive semen samples from 427 men, collected in our Department from January 2008 to December 2009, then we re-evaluated those results using WHO 2010 parameters; we also studied each parameter to understand how changed the classification from normal (defined normal by all parameters) to abnormal (defined abnormal by at least one parameter) using the two WHO criteria. Results: 3 men (0.56%) were azoospermic. Among the remaining 526 samples, 199 (37.83%) were considered normal and 246 (46.76%) abnormal both according to WHO 1999 and WHO 2010 criteria; we found that none of the samples classified normal according to the previous criteria was classified abnormal according the more recent criteria, while 82 (15.58%) evaluated as abnormal according 1999 criteria changed to normal according 2010 criteria. The concordance between 1999 and 2010 evaluation was 84.44%. Conclusions: In this study we noted that the changes from WHO 1999 to WHO 2010 criteria did not modify the interpretation of semen quality, because comparing the two classifications we demonstrated that there is a substantial agreement, considering the three parameters (count, motility and morphology) all together, and also considering each single parameter. Anyhow, almost 16% of the patients considered infertile according to the old criteria, should be evaluated normal by the new classification and they should not need any treatment for infertility.