Diagnostic accuracy of computer-assisted sperm motion analysis

One retrospective and two prospective studies were conducted among 218 coup les treated with in-vitro fertilization (IVF) to establish the reproducibil ity and diagnostic accuracy of computer-assisted sperm analysis (CASA) with swim-up spermatozoa for the prediction of the fertilization rate of oocyte s in vitro, Based on the results of a preliminary retrospective analysis in 49 patients, the 'curvilinear velocity' (VCL) was chosen as the most disti nctive motion parameter of sperm function and the median was used to repres ent the entire sperm population, The number of inseminated motile spermatoz oa was then adjusted to median VCL during two subsequent prospective studie s with clinical IVF, Whereas in the first prospective study (90 couples) th e threshold values of VCL with regard to the number of spermatozoa insemina ted were based on the results of the preliminary retrospective study (49 co uples), in the second prospective study (79 couples) the settings were base d on the results of the first prospective study. The reproducibility of CAS A was tested by analysing the motion characteristics of spermatozoa at diff erent intervals after termination of swim-up, by repeated analysis of the s ame video-recording of the incubated spermatozoa by different observers, an d by the repeated video-recording of the freshly prepared sperm samples and analysis of both video-recordings by the same observer. Under these condit ions the frequency of disagreement between two measurements varied between 2.0 and 8.2%, In both prospective studies the sensitivity of CASA for the p rediction of fertilization was high (74.0%), whereas the specificity was lo w (40.0%), In contrast to successful fertilization, unsuccessful fertilizat ion of oocytes in vitro could not be predicted reliably with CASA, However, the pregnancy rate per cycle among patients,vith predicted low fertilizati on rates was significantly lower (5.3%) than in couples with high predicted fertilization rates (24.3%, P < 0.001). Therefore, CASA of washed spermato zoa may still help to identify couples who would benefit more from intracyt oplasmic sperm injection (ICSI) than from IVF, A definite threshold level c ould not be identified for any of the motion parameters to distinguish the motion characteristics of fertilizing and non-fertilizing spermatozoa, Usin g various algorithms for hyperactivated motility, the percentage of hyperac tivated spermatozoa was significantly higher among the successfully fertili zing patients than among the nonfertilizing group. However, the absolute nu mber of hyperactivated spermatozoa added to the oocytes was higher in non-f ertilizing couples, Therefore, the lack of fertilization in some patients m ay be caused by a generalized defect in sperm function rather than by insuf ficient hyperactivation.