Viability Stained Smear: Red = Dead White = Live
If a sperm isn't moving, is it dead or does it have a motility defect?
Many accreditation agencies require a viability test to differentiate live and dead sperm in cases of low motility (less than 25-30%). Typically, most of the non-moving sperm are dead. But in some cases, for example Kartagener's syndrome, an ultrastructural defect of the axoneme makes the sperm unable to swim but does not impair viability. The difference can have a significant effect on diagnosis and treatment.
The easiest viability method uses staining based on cell membrane exclusion. Our stain kit contains eosin Y as the primary exclusion stain coupled with nigrosin counterstain. The extra nigrosin step takes only a few seconds and makes the sperm much easier to detect. Each of the stains is packaged in a dropper bottle dispenser for easy application. Just combine 1 drop of semen with 2 drops of eosin Y, mix well, add 3 drops of nigrosin, mix, and smear. As soon as the smears dry, analyze 200 and the test is done. Live cells exclude the stain and appear white. Dead sperm are stained pink.