Uncommonly Used Sperm Tests
Post-coital testing (PCT) involves evaluating the woman’s cervical mucus microscopically for the presence of sperm following intercourse. The test must be performed in the peri-ovulatory period (when the cervical mucus is most receptive to sperm) and approximately two to eight hours after intercourse. A normal test result is defined as more than 10 sperm per high power field (hpf) under the microscope.
PCT is not commonly performed, but it may be useful when there is concern regarding sperm delivery to the cervical mucus. Potential reasons for ordering PCT testing include:
1) Hyperviscous semen
2) Unexplained infertility
3) Low volume ejaculate with normal sperm count
4) Evaluating the fertility potential of men who are not able to produce a specimen either with masturbation or with a special collection condom
5) Concerns about cervical problems
6) Proximal hypospadias when there are concerns that sperm are not being deposited near the cervix
Other Even More Rarely Used Fertility Tests
Other fertility testing methods that are not used much anymore include several tests to evaluate the sperm/egg interactions needed for normal egg fertilization. In the pre-ICSI era, this was important information, as only standard IVF was available, in which about 100,000 sperm were mixed with each egg in a sterile laboratory dish, so the sperm and egg had to interact together normally. These interactions include such necessary steps as capacitation (biochemical changes within the sperm when it enters into the female reproductive tract that make it able to fertilize an egg) and acrosome reaction (when the sperm binds to the zona pellucida surrounding the egg, it initiates the acrosome reaction within the sperm, causing a release of enzymes from the acrosome cap, which allows the sperm to penetrate the egg and initiate fertilization).
The ability to perform intra-cytoplasmic sperm injection (ICSI), in which a single sperm is injected directly into each egg, has made the determination of egg-sperm interactions less important. Poor fertilization rates with standard IVF are now routinely managed with IVF/ICSI, thereby bypassing the need for cumbersome egg/sperm interaction testing. These tests are briefly described for historical purposes only, as they are only rarely used now. These outdated tests include:
Acrosome reaction testing
The acrosome reaction test was designed to see if the sperm has a normal release of acrosomal enzymes. Used in the past for men with profound abnormalities of sperm heads and in couples with standard IVF failure. Downsides included no absolute cutoffs for normal values and limited lab availability.
Sperm penetration assay
Tests the ability of sperm to penetrate an egg to initiate fertilization. Sperm are mixed in the lab with hamster ova and evaluated for their ability to penetrate the egg.
Sperm zona binding
Tests the ability of the sperm to attach to the zona pellucida (outer covering of the egg).