zona-free hamster egg penetration test
Also written as: SPA — sperm penetration assay
Laboratory assay using hamster eggs to evaluate human sperm's ability to penetrate and fertilize.
Full Definition
The zona-free hamster egg penetration test, also known as the sperm penetration assay (SPA), is a functional test of sperm fertilizing capacity. This test involves removing the zona pellucida from hamster eggs and exposing them to capacitated human sperm to assess penetration ability. The test provides information about sperm membrane fusion capability and acrosome reaction competence that cannot be determined from standard semen analysis. While historically used in male fertility assessment, this test has largely been replaced by more direct measures such as ICSI success rates and improved sperm function tests.
Usage
Usage note: Largely superseded by modern fertility testing methods
In Context
- "The zona-free hamster egg penetration test showed normal sperm function." — Laboratory report
- "SPA testing may be considered for unexplained fertilization failure." — Clinical protocol