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Chromosomal Microarray, Prenatal, ClariSure® and 5-Cell Chromosome, Amniotic
Test Code14112
CPT Codes
88235, 88261
Includes
If results are not possible from the originally ordered Cytogenetics test, the test will be cancelled and automatically replaced with non-orderable test code Cytogenetics Communication for reporting purposes.
Preferred Specimen
30 mL amniotic fluid collected in a sterile screw-cap container
Minimum Volume
10 mL
Other Acceptable Specimens
Cultured cells collected in each of two T25 flasks at 70-100% confluency
Transport Temperature
Room temperature
Specimen Stability
Specimen viability decreases during transit. Send specimen to testing laboratory for viability determination. Do not freeze. Do not reject.
Methodology
Oligo-SNP Array • Culture • Microscopy • Karyotype
Setup Schedule
Monday-Sunday All Shifts Report available: 9 Days
Reference Range
See Laboratory Report
Clinical Significance
Per the joint recommendation by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal‐Fetal Medicine (SMFM), prenatal chromosomal microarray (CMA) testing is frequently ordered on amniotic fluid (AF) and chorionic villus samples (CVS). CMA provides information on copy number abnormalities as well as regions of homozygosity (ROH). It can provide clinically actionable information at a higher resolution than chromosome analysis. However, CMA cannot detect balanced translocations, inversions, or a certain type of tetraploidy. When a normal CMA result is achieved, an abbreviated (5 cells or 5 colonies) chromosome analysis is sufficient to detect the balanced rearrangements that are missed by CMA. Although the information provided by CMA is usually sufficient to interpret the clinical significance of the CMA findings, for some abnormal results, the mechanism of the underlying numerical or structural chromosomal abnormality cannot be determined by CMA alone (e.g. simple trisomy vs. trisomy resulting from a Robertsonian translocation, tandem gain vs. supernumerary chromosome or derivative chromosome, etc.). Chromosome analysis can characterize the underlying mechanism, which can aid in genetic counseling and calculation of recurrence risk. For this reason, it is not uncommon to have chromosome analysis added after a stand-alone CMA result. However, this practice delays turnaround time and increases cost. An abbreviated (5 cells or 5 colonies) chromosome analysis of cultured cells provides sufficient information for characterization of the abnormality found in non-mosaic CMA analysis.
