Primed in situ labeling for rapid prenatal diagnosis

OBJECTIVE: Our purpose was to assess the feasibility of primed in situ labeling for analysis of prenatal diagnostic specimens. STUDY DESIGN: Prenatal diagnostic specimens were chosen at random for analysis without knowledge of clinical indication. Primed in situ labeling with primers for chromosomes 18, 21, X, and Y was performed separate from conventional cytogenetic analyses. All clinical management considerations were based solely on conventional cytogenetic analyses. RESULTS: Forty-one samples were analyzed by primed in situ labeling: 35 direct preparations of chorionic villi and 6 uncultured amniotic fluid samples. In all cases analysis confirmed the particular chromosome number determined by conventional cytogenetic analysis. CONCLUSIONS: Although conventional metaphase studies remain the standard for prenatal cytogenetic analyses, the preliminary feasibility study finds primed in situ labeling to be a rapid and reliable adjunctive diagnostic technique applicable for prenatal diagnosis in certain clinical situations. Further study is needed to assess the efficacy of primed in situ labeling in comparison to fluorescent in situ hybridization and conventional cytogenetic analyses for prenatal diagnoses. (Am J Obstet Gynecol 1998;178:1313-20.)