poor results while later samples show normal results. A man may prefer to produce his sample at home rather than at the clinic. The site of semen collection does not affect the results of a semen analysis.. If produced at home the sample should be kept as close to body temperature as possible as exposure to cold or warm conditions can affect sperm motility Measurement methods Volume can be determined by measuring the weight of the sample container, knowing the mass of the empty container. Sperm count and morphology can be calculated by microscopy. Sperm count can also be estimated by kits that measure the amount of a sperm-associated protein, and are suitable for home use. Computer assisted semen analysis (CASA) is a catch-all phrase for automatic or semi-automatic semen analysis techniques. Most systems are based on image analysis, but alternative methods exist such as tracking cell movement on a digitizing tablet. Computer-assisted techniques are most-often used for the assessment of sperm concentration and mobility characteristics, such as velocity and linear velocity. Nowadays, there are CASA systems, based on image analysis and using new techniques, with near perfect results, and doing full analysis in a few seconds. With some techniques, sperm concentration and motility measurements are at least as reliable as current manual methods. Raman spectroscopy has made progress in its ability to perform characterization, identification and localization of sperm nuclear DNA damage. See also Semen quality Artificial insemination for more details of how semen parameters affects pregnancy rate References External links Blood in semen Hematospermia Geneva Foundation for Medical Education and Research - complete list of parameters. WHO laboratory manual for the examination and processing of human semen Fifth edition 2010 - updated, standardized, evidence-based procedures and recommendations for laboratory analysis and quality control Fertility medicine Semen