Reveal SNP Microarray and Abbreviated Chromosome Analysis (CVS)

CPT:

81229; 88235; 88261. If additional testing is performed, concomitant CPT codes/charges will apply.


Test Includes

DNA extraction; interpretation; limited five-cell chorionic villus sample (CVS) chromosome analysis (two analyses, one karyotype)


Special Instructions

If the specimen does not meet minimum DNA quality and quantity requirements, array testing will be performed on cultured material. This test is currently not orderable by New York State clients. A completed Clinical Questionnaire for SNP Microarray should accompany specimens. Concurrent maternal contamination (MCC) studies are required.​



Specimen Requirements


Specimen

Chorionic villus sample (CVS). Gender by ultrasound is recommended, when possible. Submit maternal blood (sodium heparin or EDTA) for maternal cell contamination studies. 


Volume

20-30 mg (for concurrent array and chromosomes)


Minimum Volume

5 mg (CVS minimum)


Container

CVS transport tube; sterile specimen container with transport medium


Collection

Specimen is collected in syringe (transabdominal) or catheter (transcervical) and transferred by flushing with the media from the sterile container back into it. After collecting the specimen, wash with sterile saline solution (NaCl 0.95%) containing sodium heparin (two to three drops of sodium heparin in 10 mL of saline). Carefully transfer the specimen, into the CVS transport tube, using a sterile Pasteur pipette or a sterile fine-needle forceps. Be sure to fill transport tubes completely with medium. Samples from twin (multiple) pregnancies should be appropriately labeled and placed in separate transport containers with a separate test request form for each twin.


Storage Instructions

Maintain specimen at room temperature, and transport it to the cytogenetics laboratory immediately. Do not freeze. Refrigerate if sterility is questioned or if sample cannot be shipped within 24 hours.


Causes for Rejection

No villi submitted in specimen; improperly labeled specimen; frozen specimen; specimen placed in fixative


Test Details


Use

Microarray detects chromosomal imbalance that could be associated with developmental delay and congenital anomalies. Test provides detection of uniparental disomy of any chromosome, the percentage and location of homozygosity, including the degree of identity by descent. Abbreviated chromosome analysis detects balanced rearrangements. This test is used to rule out tetraploidy and rearrangements not detected by microarray, such as balanced translocations and inversions.


Limitations

This SNP assay does not detect balanced rearrangements and may not detect low-level mosaicism.


Methodology

Whole genome SNP-based copy-number microarray analysis targeting 2.695 million copy-number and allele-specific genome sites from uncultured cells. If DNA yield on uncultured cells is inadequate, analysis will be performed on cultured cells. Five-cell G-band chromosome analysis.


Pregnancy Week

0–13 Weeks
14–21 Weeks
22+ Weeks

References

Coppinger J, Alliman S, Lamb AN, et al. Whole-genome microarray analysis in prenatal specimens identifies clinically significant chromosome alterations without increase in results of unclear significance compared to targeted microarray. Prenat Diagn. 2009 Dec; 29(12):1156-1166.PubMed 19795450

Wapner R. A multicenter, prospective, masked comparison of chromosomal microarray with standard karyotyping for routine and higher risk prenatal diagnosis. Am J Ob Gyn. 2012 Jan; (Suppl). Abstract 1.


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