CASA—Practical Aspects

Abstract

When computer-aided sperm analysis (CASA) instruments were first brought into the marketplace in the mid-1980s, it was suggested that these machines could replace the laboratory andrologist because they could provide concentration and percentage motile values for a sample, as well as give population values for aspects of sperm movement (kinematics). Unfortunately, this hope was not realized when it was shown that these early-generation machines did not provide sufficiently accurate results to act as semen analyzers (Mortimer and Mortimer, 1988, 1998). Despite the fact that CASA instruments at that time were really only designed, and therefore only suitable, for research applications, the disappointment in their apparent failure to perform as purported tarnished the reputation of CASA and delayed development of the field. It is only in relatively recent times that there has been a positive and concerted action to define the role of CASA in both the clinical andrology laboratory and in the research laboratory. There have been three international consensus meetings in which aspects of the use of CASA have been discussed and guidelines published (Mortimer et al, 1995; ESHRE Andrology Special Interest Group, 1996, 1998). The aim of these meetings was to attempt to standardize the methods and applications of CASA so that there would be the highest likelihood of useful clinical and research data being generated and applied throughout the world. The importance of such an aim cannot be overestimated in the use of CASA. CASA is potentially a very powerful research and clinical tool. Indeed, its inclusion in reproductive toxicology studies indicates its relevance (Slott et al, 1993, 1995, 1997), but its features and limitations must be understood quite clearly before attempting to make clinical diagnoses on the basis of its results (ESHRE Andrology Special Interest Group, 1998).