Repeatability and variance analysis on multiple computer-assisted (IVOS*) sperm morphology readings

The repeatability of the Hamilton Thorne Research IVOS (version 10) semen a nalyser (dimension specific software, version 3) in the evaluation of sperm morphology according to strict criteria was investigated in this study. Th e repeat measures investigated were cell-cell (300 cells, 3 x each), intras lide (20 slides, 3 x each) and interslide (30 samples, 3 slides each), and their normal sperm morphology outcomes were recorded. Semen samples with va rying normal sperm morphology percentages were obtained and sperm morpholog y slides prepared. The slides were stained with Diff-Quik stain. Agreements between evaluations were determined using the kappa statistic and average coefficients of variation. The predictive probability for an abnormal cell given a prior abnormal cell outcome was 91%, and 89% for a similar predicti on of a normal cell. The predictive probabilities for an abnormal or a norm al cell given two prior abnormal or two prior normal cell outcomes were 95% and 94%, respectively. No significant bias was obtained between the repeat probabilities for normal and abnormal sperm cells. The average coefficient s of variation for the intraslide trial were 9.73% and 8.30% when 100 and 2 00 sperm cells were evaluated, respectively. The average coefficient of var iation for the interslide trial was 15.39%. The technical importance of goo d sample and slide preparation technique has once again been highlighted by this study. A uniform (spatial homogeneity), high concentration (5-10 cell s per computer screen) smear must be made and the cells stained with optima l intensity (maximum contrast). In a trial in which 2000 cells were evaluat ed, 19 objects (0.95%) were identified as spermatozoa, but were debris. The automated semen analysing system (IVOS) used in this study was shown to ma intain a level of repeatability, precision and accuracy acceptable for the application of the system in a routine semen analysis situation.