COMPUTER-AIDED SEMEN ANALYSIS - SPERM CONCENTRATION ASSESSMENT BY THESTROMBERG-MIKA SYSTEM

The scope of this study was to evaluate the accuracy, precision and sp ecificity of the sperm concentration measurements by the Stromberg-Mik a Cell Motion Analyser (SM-CMA). Our data show that the instrument gen erally underscores the sperm concentration and therefore the uncorrect ed measurements must be corrected by the operator using the 'mouse'-dr iven option. In terms of precision, the system appears to have an exce llent internal precision whereas its repeatability is influenced by th e sperm concentration, the sample's homogeneity and the correction of the raw data. In order to increase the system's repeatability, we sugg est that sperm counts should be carried out in various fields of the c ounting chamber, and the mean of the corrected values be taken as repr esentative of the sperm concentration in the ejaculate if the various measurements show a homogenous (poissonian) distribution. The correcti on of the raw data with the 'mouse'-driven correction option was also shown to improve the system's reproducibility. Concerning specificity, our data evidenced that, without technical correction, the instrument failed to correctly classify certain spermatozoa as such, thereby gro ssly underscoring sperm counts. This finding was more evident at low s perm counts. Overall, the SM-CMA requires additional laboratory time b ut the corrected sperm counts are comparable to manual counts and semi -automated counts with the added option that it provides the andrologi sts with various motility characteristics not possible with the latter methodologies.