External quality control and training of semen analysis in the Netherlands: starting point for further reduction of outcome variability.

There was a decreasing trend for interlaboratory CVs of sperm concentration assessment (range: 24.0%–97.5%, in 2001–2004), toward a more stable period in 2015–2018 (range: 12.7%–20.9%).

also in 47,180 other papers