Seminogram value that indicates the percentage of live spermatozoa (motile or immotile) found in a semen sample, which must be equal to or greater than 58% for a semen sample to be considered normal. If it is lower, it is considered necrozoospermia. Viability is a crucial factor in fertility, as a high number of dead or immotile sperm reduces the chances of natural conception. Sperm viability is a metric that can be measured by semen analysis.