The microsperm penetration assay: development of a sperm penetration assay suitable for oligospermic males.
OBJECTIVE
To develop a specialized sperm penetration assay (SPA) for the evaluation of sperm from oligospermic patients.


METHODS
The development of the assay is in four parts: determine optimal sperm number; demonstrate quality control; establish statistical limits for fertile population; compare results to in vitro fertilization (IVF) outcome.


METHODS
A group of 63 patients with oligospermia and/or poor motility and a group of 17 fertile donors were compared using the optimized SPA and the micro-SPA. Sperm from a third group of 35 patients were simultaneously incubated with human ova (IVF) and hamster ova (micro-SPA).


METHODS
Both types of SPA scores are expressed as a sperm capacitation index (penetrations per ovum). Outcome of IVF is expressed as a percent of ova fertilized.


RESULTS
Using 25,000 sperm was found to be optimal. The normal fertile range was statistically determined to have a lower limit (-2 SD) of 2.0 penetrations per ovum. When scores from 63 male factor patients were compared using the optimized SPA, only 43% had sufficient swim-up sperm. However, the micro-SPA could accurately test 100% of the samples because it requires only one tenth the number of sperm.


CONCLUSIONS
The micro-SPA provides a valuable diagnostic test for the evaluation of the male factor patient.
Johnson
A
A
Scott Department of Urology, Baylor College of Medicine, Houston, Texas 77030.
Smith
R G
RG
Bassham
B
B
Lipshultz
L I
LI
Lamb
D J
DJ
D000818:Animals; D006224:Cricetinae; D005188:False Negative Reactions; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008647:Mesocricetus; D009845:Oligospermia / Q000175:diagnosis*; D011786:Quality Control; D012680:Sensitivity and Specificity; D013076:Sperm Count; D013084:Sperm-Ovum Interactions