PROBABILITY TABLES FOR EXCLUSION OF MOSAICISM IN PRENATAL-DIAGNOSIS

The decision concerning the number of metaphases that need to be analy sed to detect mosaicism of a certain degree depends mainly, for the sa me confidence levels, on the culture method used (in situ or flask met hods). Several probability tables, designed for either the in situ or the flask method, have been reported and can be used to assist laborat ories in making the decisions referred to above. However, there are in stances where part of the analysis is done using the in situ and flask methods. In such situations, the previously published tables are of l imited use. We have generated a new table that can be used in such sit uations, as well as in cases where only the flask method is used. (C) 1997 by John Wiley & Sons, Ltd.