TY - JOUR ID - 45346 TI - Reducing Inter-Laboratory Differences between Semen Analyses Using Z Score and Regression Transformations JO - International Journal of Fertility and Sterility JA - IJFS LA - en SN - 2008-076X AU - Leushuis, Esther AU - Wetzels, Alex AU - van der Steeg, Jan Willem AU - Steures, Pieternel AU - Bossuyt, Patrick M.M. AU - van Trooyen, Netty AU - Repping, Sjoerd AU - der Horst, Frans A.L. van AU - Hompes, Peter G.A. Hompes AU - Mol, Ben Willem J. AU - der Veen, Fulco van AD - Department of Obstetrics and Gynecology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands;Academic Medical Center, Center for Reproductive Medicine, Amsterdam, The Netherlands AD - Radboud University Nijmegen Medical Centre, Department of Obstetrics and Gynaecology, Nijmegen, The Netherlands AD - 4Jeroen Bosch Ziekenhuis, Department of Obstetrics and Gynaecology, ’s-Hertogenbosch, The Netherlands AD - 5University Medical Center Utrecht (UMC Utrecht), Department of Obstetrics and Gynaecology, Utrecht, The Netherlands AD - 6Academic Medical Center, Department of Clinical Epidemiology and Biostatistics, Amsterdam, The Netherlands AD - 7Department of Clinical Chemical, St. Antonius Hospital, Nieuwegein, The Netherlands AD - 8Diagnostic Center SSDZ Reinier De Graaf Group, Department of Clinical Chemistry, Delft, The Netherlands AD - Department of Obstetrics and Gynecology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands AD - Academic Medical Center, Center for Reproductive Medicine, Amsterdam, The Netherlands Y1 - 2016 PY - 2016 VL - 9 IS - 4 SP - 534 EP - 540 KW - Differences KW - Semen analysis KW - Regression KW - standardization DO - 10.22074/ijfs.2016.4613 N2 - 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 CVBwas 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. UR - https://www.ijfs.ir/article_45346.html L1 - https://www.ijfs.ir/article_45346_05ae3d0f75e8a75f4f54f03312933913.pdf ER -