IUI insemination (introduction of washed sperm into the uterus) should occur during a period of time when sperm Fc receptor (FcR) expression is going through a minimum, i.e., in a window of time about the minimum. In order to be ready to inseminate at the time when the FcR expression goes through a minimum, sperm are prepared for insemination according to standard practice. Time of the IUI procedure itself is adjusted to occur at the preferred sperm state, again within the clinic's permitted timeframe for the physician to treat the patient by instilling the washed sperm into the uterus. The level of FcR expression is determined by time-based assay and insemination is performed based on the fertility state of sperm as determined by the assay.
