Quality assessment of computer-assisted semen analysis (CASA) in the andrology laboratory

If quality is assessed with regard to computer-assisted semen analysis (CASA), the evaluation of seminal fluid in the andrological laboratory has to be considered. Three levels of quality assessment are generally accepted: structure, process and results. Quality of structure mainly concerns the quality of laboratory assessment, in particular the skill of the staff and the equipment used. The quality of the CASA system itself is difficult to assess. Process quality concerns the quality of performing a diagnosis. When the parameter settings of the CASA system and the handling of the sample are defined, the reproducibility of the CASA values is clearly better than that of the visual estimation of motility. CASA systems are also superior to other methods regarding the documentation of laboratory values, as all the values are obtained directly online. Result quality comprises the precision, reliability and reproducibility of measurement as well as the significance of values with respect to their biological relevance. Concluding from the definitions as quoted above and from reports of the literature it may be stated that: (i) in the dimensions of structure and process quality, CASA is superior to other methods of measuring sperm motility; (ii) the evaluation of results and quality of results, however, is highly problematic; (iii) CASA systems do not appear to be superior to the visual estimation of sperm motility with respect to the fertilizing capacity of spermatozoa; (iv) the guidelines of the WHO task force form a basis for sufficient process quality; (v) further efforts should actually focus not on the improvement of investigation technology, but on the improvement in the qualification of investigators.