Receiver-operating characteristics curves for semen analysis variables: methods for evaluating diagnostic tests of male gamete function

Association between sperm cell chromatin condensation, morphology based on strict criteria, and fertilization, cleavage and pregnancy rates in an IVF program

In this study, a total of 95 ejaculates from infertile patients were investigated morphologically according to Kruger's strict criteria and 78 of the 95 ejaculates were stained for chromatin condensation with acidic aniline blue. Patients were divided into two groups based on the percentage of morphologically normal spermatozoa as follows: Men with normal sperm morphology < 14% (Group 1), and men with normal morphology > 14% (Group 2). The relationship between percentage of normal sperm morphology and fertilization, cleavage and pregnancy rate was analysed. The rates were 33.7%, 57.1% and 0.0% respectively, in the first group. The corresponding values for the second group were 76.1%, 68.2% and 32.1%. The fertilization and pregnancy rates correlate significantly with morphologically normal spermatozoa. In regard to the percentage of morphologically normal spermatozoa stained with aniline blue, patients were divided into two groups: patients with 0-20% stained spermatozoa (Group I) and those with > 20% (Group 2). Fertilization and pregnancy rates were higher in the first group than in the second group (79.9%, 52.8% vs. 58.8%, 29.5%). The results demonstrate that chromatin condensation visualized by aniline blue staining is a good predictor for IVF outcome and should be considered besides morphology by sperm assessment for patients undergoing IVF treatment.

Value of sperm characteristics and the result of in-vitro fertilization for predicting the outcome of assisted reproduction

The outcome of procedures for assisted reproduction, namely in-vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT) were used as end-points to assess the capacity of particular sperm characteristics to predict the fertilizing potential of semen. In addition, the result of IVF performed with spare oocytes from the GIFT procedure, was used to predict the pregnancy outcome of GIFT. The power of sperm characteristics to predict the outcome of assisted reproduction procedures was poor. With regard to the outcome of IVF, sperm morphology was the best discriminant. The threshold value of 16% normal sperm morphology could be used as a good predictor of successful IVF, but could not be applied as a criterion to reject an IVF trial. For the latter purpose, the limit of 5% sperm with normal morphology should be used. The proportion of sperm with grade A motility in native semen provided the best discrimination between GIFT-fertile and GIFT-infertile cases. A negative result from IVF performed with spare oocytes was 93% accurate in predicting unsuccessful outcome of GIFT. Hence, diagnostic IVF is the most sensitive assay for male fertility. The occurrence of oocyte fertilization during IVF predicts a successful outcome of GIFT in only 50% of cases. Hence, a negative result in IVF indicates that semen is almost certainly infertile, but a positive result does not guarantee the successful outcome of GIFT.

Capacity of objectively assessed sperm motility characteristics in differentiating between semen of fertile and subfertile men

A simple and inexpensive computer-assisted method for the objective assessment of sperm motility characteristics was employed to evaluate semen samples of 42 fertile men and 70 subfertile patients. The capacity of each motility parameter to discriminate between semen of the two groups was evaluated by receiver operating characteristic curve analysis. Velocity, linear velocity, and "angular" velocity are reasonably accurate, whereas linearity and angularity index had a very poor discriminating power. The best discrimination between the two groups was the proportion and concentration of sperm with rapid linear progressive motility, based on the cut-off value of linear velocity greater than or equal to 22 microns/sec. This parameter was 90% accurate in discriminating semen of infertile men from that of subfertile patients.