New Search

Laboratory Test Directory

Prenatal Microarray with 5-Cell Chromosome Analysis (No Parental Testing)

Components

Name Method Department Units
Prenatal Microarray with 5-Cell Chromosome Analysis DNA extraction
Microarray analysis
Cell Culture
Chromosomal analysis
Molecular Genetics

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Required

Purple tube (EDTA)

6 mL 3 mL-6 mL
Stability

Room temperature - 24 hour(s)
Refrigerated - 72 hour(s)

Specimen Preparation

  • Keep at room temperature or refrigerate

Amniotic fluid

Container Type Container Size Specimen Volume
Required

Sterile container

N/A 30 mL or greater
Stability

Room temperature - 24 hour(s)

Specimen Preparation

  • Do not add fixative
  • Do not freeze
  • Transport to the lab immediately after collection
  • Do not refrigerate
  • Keep at room temperature
  • Protect from cold.
  • Protect from heat

Reasons for Rejection

  • Delayed or improper handling
  • Fixed specimen
  • Frozen specimen

Comments

Submission of completed Prenatal Genetic Test Requisition Form is required. Submission of maternal blood specimen (4mL EDTA) is required for maternal cell contamination. To obtain a test requisition form, please call (614) 722-5321 and speak with a laboratory genetic counselor. If the mother and the father of pregnancy are known to be consanguineous, please provide reported parental relationship information on the requisition form.

This test includes prenatal microarray analysis and abbreviated 5-cell chromosome analysis. PLEASE NOTE: maternal and paternal microarray/FISH analyses are not included in this study. Prenatal microarray analysis can be performed on direct amniotic fluid specimen or on cultured amniocytes (cells grown from amniotic fluid). Minimum of 20 mL amniotic fluid specimen is needed to perform this test on direct amniotic fluid (add 5 mL fluid if also ordering Aneuploidy FISH Screen, and add 10 mL fluid if also ordering send-out testing). If submitted fluid volume is insufficient for direct amniotic fluid microarray analysis, then cells in fluid will be cultured first for microarray analysis. For direct amniotic fluid microarray analysis, results are typically available within 10-14 days from the day specimen received by the laboratory. If cells must be cultured first before microarray analysis can be performed, then results are typically available within 2-3 weeks from the day specimen received by the laboratory. Amniotic fluid chromosome analysis can be performed concurrently with, prior to, or as a reflex test to this prenatal microarray analysis.

For 5-cell chromosome analysis, cells in amniotic fluid specimen will be cultured, and the number of chromosomes will be evaluated in 5 cultured cells and the full karyotype analysis will be performed on 1 of the 5 cells.

PLEASE NOTE: Due to the limited number of cells evaluated by this study for chromosome analysis, mosaicism for chromosomal abnormality may not be detected by this study. If mosaicism is suspected, an alternate testing "Amniotic Fluid Chromosome Analysis (test code: AFST)" that evaluates 15 colonies is available, with an option for "Mosaicism Study" that evaluates additional number of colonies.


This chromosomal (whole genome) microarray analysis uses a combination of oligonucleotide probes as well as SNP probes. Detection of DNA copy number abnormalities is performed by comparative genomic hybridization (CGH) analysis using ~135,000 oligonucleotide probes, while detecton of the regions of homozygosity (ROH, also known as long contiguous stretch of homozygosity) is done by single nucloeotide polymorphism (SNP) analysis using ~67,000 SNP probes.

Chromosomal microarray analysis evaluates DNA copy number across the genome at higher resolution than chromosome analysis. It can detect submicroscopic genomic losses and gains not detectable by chromosome analysis, as well as large genomic losses and gains that are detectable by chromosome analysis (such as trisomies, monosomies, triploidy, unbalanced translocation or inversion products). Chromosomal microarrays that incorporate single nucleotide polymorphism (SNP) probes can detect large regions of homozygosity (ROH). Presence of ROH is not diagnostic of any disorder, but it can suggest increased risk for two different classes of genetic disorders: disorders of imprinting (uniparental disomy; UPD) and recessive disorders. Evidence suggestive of a blood relationship between the parents (parental consanguinity) also may be revealed.

PLEASE NOTE: Microarray analysis may not be able to detect the presence of mosaism if abnormality is present in less than 30% of cells. Microarray analysis also cannot detect balanced chromosomal rearrangements such as a balanced translocation or inversion.

CPT Code

  • 81229
  • 88235
  • 88261
  • 81265