Several methods can be used to analyze samples obtained from CVS and amniocentesis procedures. The following is a very brief summary of those methods:
Karyotype analysis
Karyotype is the number and appearance of chromosomes in the nucleus of a cell. Karyotype analysis involves the cytogenetic staining of the chromosomes in the specimen with follow-up microscopic analysis to determine the total number and size of chromosomes, the sex, and any structural abnormalities with individual chromosomes. Karyotype analysis is considered the gold standard for chromosomal analysis of CVS and amniocentesis samples.
Fluorescence in situ hybridization (FISH)
Fluorescent in situ hybridization (FISH) is a molecular cytogenetic technique that uses fluorescent probes that bind or hybridize to only those parts of the chromosome with a high degree of complementary sequence. FISH can detect and localize the presence or absence of specific DNA sequences on chromosomes. The technique is typically performed using a fluorescence microscope to identify where the fluorescent probe is bound to the chromosomes. FISH is a rapid way to detect common fetal aneuploidies and is often used in conjunction with karyotyping analysis.
