Exclusion of chromosomal mosaicism in prenatal diagnosis.

For use in prenatal diagnosis, tables were prepared giving the number of metaphases or clones, respectively, which must be analysed in order to detect fetal mosaicism of a given degree (= percentage of the aberrant cell population) or higher with at least 95% or 99% probability. Different tables are provided for the two techniques of chromosomal preparation: the colony method and the flask method.