Combined supravital staining and hypoosmotic swelling test.

The parameter of sperm viability in hypoosmotic solution (VHOS) provides information concerning the membrane integrity of the sperm head. The objective of this study was to determine the association between the VHOS parameter and the sperm penetration assay. The VHOS parameter correctly predicted 70.0-71.4% of the failed sperm penetration assay samples in the short duration preincubation groups. A combination of both the VHOS parameter and the hypoosomotic sperm swelling (HOS) test significantly reduced the number of false negative results. In general, a sperm sample with an abnormal VHOS result and an abnormal HOS test result would be associated with a negative sperm penetration assay. Washing by centrifugation appeared to weaken the sperm head membranes while the swim-up method selected for sperm with strong head and tail membranes. After the various processing methods unique changes in the integrity of the sperm head and tail membranes for each sperm sample may help to identify the optimal method of preparation for individual patients undergoing the newer assisted reproductive technologies such as sperm microinjection.