Interphase FISH for Prenatal Diagnosis of Common Aneuploidies

Cytogenetic analysis is currently a standard prenatal diagnostic test. It is routinely offered to pregnant patients who have an increased risk of carrying chromosomally abnormal fetuses. The traditional “gold standard” for prenatal diagnosis of chromosome abnormalities is metaphase analysis by G-banding. The primary advantages of standard cytogenetic analysis are the ability to detect aneuploidies as well as structural chromosomal aberrations with great accuracy (<99.5%). Traditional karyotyping, however, requires isolation of metaphase chromosomes from cultured fetal cells and therefore is time consuming. Although reporting time has decreased dramatically during the last 3 decades, conventional karyotyping still requires 7–12 d of which culture time is the most time consuming (1 ).