Abnormal fetal ultrasound findings with a normal karyotype
De novo apparently balanced chromosomal rearrangement
Identification of marker chromosome
Desire for additional information not provided by routine karyotyping
Baby/child with multiple congenital anomalies, developmental delay/mental retardation, or autism
POC samples for which chromosome studies fail
Prenatal: 30 cc of amniotic fluid or 20 mg of chorionic villi tissue if fetal microarray analysis is requested on direct amniotic fluid or chorionic villi for a quicker turnaround time. 20 cc of amniotic fluid or 10 mg of chorionic villi tissue if microarray analysis is to be performed on cultured cells. 10mg of POC tissue (Fetal/villi).
Postnatal: 3-5 cc of blood collected in a green top tube (sodium heparin). It is a New York state requirement that chromosome analysis be performed prior to or concurrently with postnatal microarray analysis. Therefore, send 2 green top tubes with 3-5 cc of blood in each if both chromosome and microarray analyses are requested.
Amniotic fluid: Sterile 15 ml screw-top container
CVS: Sterile 15 ml screw cap containing sterile transport medium
POC: Sterile container containing sterile transport medium
Whole Blood Green top (sodium heparin) tubes
SNP (single nucleotide polymorphism) microarray analysis which utilizes more than 2.6 million copy and allele specific genomic sites. SNP analysis can detect copy neutral changes including uniparental disomy (UPD) and areas of homozygosity suggestive of consanguinity. Abnormal results are confirmed with Fluorescence In Situ Hybridization (FISH analysis).
Room temperature (DO NOT refrigerate, freeze, or centrifuge).
Causes for Rejection
Amniotic fluid: Frozen specimen, excessive amounts of blood, inappropriate container
CVS: Frozen specimen, absence of fetal tissue, inappropriate transport medium.
Postnatal: Frozen specimen, inappropriate container
Direct amnio, CVS or POC:7 days
Cultured cells: 7 days (additional time required for culturing is 10-14 days)
Postnatal: 7 days