Interphase Fluorescent In-situ Hybridisation or FISH, is a technique used to determine if a pregnancy is at risk of having one of the common trisomies like Down syndrome (trisomy 21). The test can be used on CVS or amniotic fluid. Targeting uncultured cells means that interphase FISH can provide: rapid results (usually within 24 hours); is useful in the investigation of mosaicism; can be used for the detection of balanced and unbalanced rearrangements; can be used for some microdeletion syndromes and known familial genetic conditions.
$175 (non Medicare rebatable)
Amniotic fluid: 15-20 ml
CVS: 10-20 mg
Interphase FISH is always followed up with either a conventional karyotype or a molecular karyotype depending on the clinical indication and the FISH result obtained.