Author/Authors :
Leushuis، Esther نويسنده Department of Obstetrics and Gynecology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands , , Wetzels، Alex نويسنده Radboud University Nijmegen Medical Centre, Department of Obstetrics and Gynaecology, Nijmegen, The Netherlands , , der Steeg، Jan Willem van نويسنده Jeroen Bosch Ziekenhuis, Department of Obstetrics and Gynaecology, ’s-Hertogenbosch, The Netherlands , , Steures، Pieternel نويسنده University Medical Center Utrecht (UMC Utrecht), Department of Obstetrics and Gynaecology, Utrecht, The Netherlands , , Bossuyt، Patrick M.M. نويسنده Academic Medical Center, Department of Clinical Epidemiology and Biostatistics, Amsterdam, The Netherlands , , Trooyen، Netty van نويسنده Department of Clinical Chemical, St. Antonius Hospital, Nieuwegein, The Netherlands , , Repping، Sjoerd نويسنده Radboud University Nijmegen Medical Centre, Department of Obstetrics and Gynaecology, Nijmegen, The Netherlands , , der Horst، Frans A.L. van نويسنده Diagnostic Center SSDZ Reinier De Graaf Group, Department of Clinical Chemistry, Delft, The Netherlands , , Hompes، Peter G.A. نويسنده Department of Obstetrics and Gynecology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands , , J. Mol، Ben Willem نويسنده Academic Medical Center, Center for Reproductive Medicine, Amsterdam, The Netherlands , , der Veen، Fulco van نويسنده Academic Medical Center, Center for Reproductive Medicine, Amsterdam, The Netherlands ,
Abstract :
Background: Standardization of the semen analysis may improve reproducibility.
We assessed variability between laboratories in semen analyses and evaluated whether
a transformation using Z scores and regression statistics was able to reduce this
variability.
Materials and Methods: We performed a retrospective cohort study. We calculated
between-laboratory coefficients of variation (CVB) for sperm concentration and for
morphology. Subsequently, we standardized the semen analysis results by calculating
laboratory specific Z scores, and by using regression. We used analysis of variance
for four semen parameters to assess systematic differences between laboratories before
and after the transformations, both in the circulation samples and in the samples
obtained in the prospective cohort study in the Netherlands between January 2002
and February 2004.
Results: The mean CVB was 7% for sperm concentration (range 3 to 13%) and 32% for
sperm morphology (range 18 to 51%). The differences between the laboratories were
statistically significant for all semen parameters (all P < 0.001). Standardization using Z
scores did not reduce the differences in semen analysis results between the laboratories
(all P < 0.001).
Conclusion: There exists large between-laboratory variability for sperm morphology and
small, but statistically significant, between-laboratory variation for sperm concentration.
Standardization using Z scores does not eliminate between-laboratory variability.
