Use of computerized karyometric image analysis for evaluation of human spermatozoa

The objective of this study was to evaluate a computer image system for its ability to determine morphological and nuclear semen characteristics in an integral and reproducible way. Semen samples from 19 normospermic fertile donors were used to estimate preliminary cutoff values for spermatozoa and to test the reproducibility of the system. Ten aliquots of 1 sample were used to investigate the sensitivity of the system for experimental conditions by exposure to different laboratory variables. Human spermatozoa were stained with Feulgen dye and analyzed with a magnification of 1000x. A panel of 21 parameters was measured for each sperm nucleus using the computerized karyometric image analysis (CKIA) system. Eight parameters were found to be sensitive for differentiating normal or abnormal human spermatozoa, and cutoff values for each parameter were defined for quantitative analysis. These 8 parameters were grouped into 3 categories depending on their descriptive value: morphometry, DNA condensation (stainability), and chromatin texture. Intrapatient and interpatient variabilities were tested by calculating the reliability coefficient for each of the 8 parameters as well as for each category. Reliability coefficients were all >70% (indicative of the suitability of the system to identify differences between spermatozoa). Interpatient variability (SD) was 5%. Although it was not statistically significant, a variation of 10.9% in measurements was found when the effects of experimental conditions were tested. We conclude that an objective description of the human sperm nucleus can be achieved with CKIA, yielding high interpatient and intrapatient reliability coefficients (reproducibility), thereby adding a new tool for the quantification of normal sperm.