Natural Killer Cells, which are part of the immune system, have been found to adversely affect pregnancy formation when elevated levels are present in the uterus.
The CD56 test is a test that allows us to understand the amount of killer cells in the uterus called the endometrium. It has been recommended for in vitro fertilization patients who have not been pregnant despite very good quality embryo transfer.
CD56 test is performed by pathological examination of a small biopsy specimen taken from the uterus on 21-24 days of menstruation. If the pathologist can determine the density of these cells by special staining techniques, it is claimed that the chance of pregnancy can be increased with appropriate treatments.