Experimental validation of seminal miR-31-5p as biomarker for azoospermia and evaluation of the effect of preanalytical variables.

Our results provide evidence that altered miR-31-5p expression can be determined both from extracellular vesicles and from the whole seminal plasma to discriminate obstructive from secretory azoospermic samples. Not only have we validated this microRNA-based molecular model as a clinically useful test for predicting the origin of azoospermia in a sample from azoospermic individuals, but additionally, and more interestingly for the clinicians, we have evidenced its usefulness for predicting the presence of spermatogenic failure in azoospermic patients with follicle-stimulating hormone values <10 IU/L as a sensitive and specific biomarker (area under the receiver operating characteristic curve >0.88; p-value < 0.006). The use of total seminal plasma as an analytical sample would facilitate the use of a simplified technical procedure for miR-31-5p quantification and would represent a great improvement in reproductive treatment decision protocols for azoospermia in clinical practice.