Influence of analytical and biological variation on the clinical interpretation of seminal parameters Castilla Alcalá, José Antonio Alvarez, C. Aguilar, J. González-Varea, C. Gonzalvo, María del Carmen Martinez, L. analytical variation biological variation quality specification semen analysis Quality assurance in semen analysis has been questioned recently in this journal. Based on the limited capacity of seminal parameter in the determination of fertility, the authors advocated abandoning methods of quality assurance in semen analysis for clinical situations. In this article, we explore arguments as to why quality assurance in semen analysis for clinical use is not 'a waste of time'. Imprecision and within-subject biological variations are the two major components involved in the dispersion of seminal parameter results obtained by analysis of a semen sample from an individual. As within-subject biological variation is constant across geography, time and population, imprecision is a very important factor in the quality of laboratory test results. We analyse this influence on various seminal parameters and observe that there is an amount of error that can be tolerated without invalidating the medical usefulness of seminal parameter determination. However, there is a maximum allowable analytical error above which the medical usefulness of seminal parameter results is invalidated. The level of performance required to facilitate clinical decision-making is termed quality specification. We comment on different strategies to define the maximum allowable analytical error. 2025-01-27T11:50:59Z 2025-01-27T11:50:59Z 2005-12-16 journal article J. A. Castilla et al. Influence of analytical and biological variation on the clinical interpretation of seminal parameters. Hum Reprod. 2006 Apr;21(4):847-51. doi: 10.1093/humrep/dei423 PMID: 16361288 https://hdl.handle.net/10481/100560 10.1093/humrep/dei423 eng open access Oxford Academic