American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

What is considered the best tissue for success rate and abnormality detection in cases of spontaneous abortion?

1. Chorionic villi

2. Amniotic fluid

3. Placental tissue

4. Fetal blood

The correct answer is: Chorionic villi

Chorionic villi are regarded as the best tissue for both success rate and abnormality detection in cases of spontaneous abortion due to their direct association with the placenta and the developing embryo. Chorionic villi are tissue projections that are part of the placenta and are involved in nutrient and gas exchange between the mother and fetus. Analyzing chorionic villi for genetic abnormalities provides a high yield of chromosomal information because they are genetically representative of the fetus. This offers insight into the genetic makeup and any chromosomal abnormalities that may have contributed to the miscarriage. When comparing other tissues, although amniotic fluid can contain fetal cells, obtaining a sample can be less straightforward, and the cells may not always represent the fetal genome accurately. Placental tissue may not always provide adequate material for analysis, especially if the early pregnancy loss results in significant tissue degradation. In contrast, fetal blood is often not available or is difficult to obtain in cases of spontaneous abortion, making it a less viable option for genetic analysis. Therefore, chorionic villi remain the tissue of choice for genetic evaluation following spontaneous abortion due to their accessibility and representativeness.