CMA - Targeted and Limited Karyotype - Prenatal - Amniotic Fluid
Use
CMA - Targeted employs array-based comparative genomic hybridization (aCGH) to precisely analyze copy number variations. It targets selective chromosomes (6, 7, 11, 14, 15, 20, and X) for detecting uniparental disomy and triploidy, making it vital for prenatal assessments. This test is especially beneficial for instances of abnormal prenatal ultrasounds, positive serum screening, or advanced maternal age, where genetic abnormalities may be a concern. The array used in this test is similar to that employed in the NICHD trial, thus promising reliability in diagnosing deletion/duplication syndromes. However, it is limited to detecting gains and losses of genetic material, excluding low-level mosaicism and balanced translocations.
Special Instructions
For this test, a detailed summary of prenatal CMA procedures is necessary. Parental samples, ideally 5 cc of whole blood in EDTA tubes, are required, with signed CMA consent recommended. Maternal cell contamination studies are carried out whenever a maternal blood sample is provided. Parental studies will be automatically conducted in cases where interpretation relies on parental data to clarify fetal results. However, some results may require parental tests on a fee-for-service basis. It's advisable that patients are informed about potential costs related to UPD analysis and that additional tests might be recommended based on AOH results from the prenatal CMA.
Limitations
The test will not report gains and losses under 1 Mb in size without associated genes and outlines exceptions for various gene-specific gains that lack clinical relevance. It also does not account for mitochondrial genome alterations or gains pertaining to adult-onset disorders, making it crucial for providers to understand the limitations surrounding prenatal CMA testing.
FDA ApprovedNew York Approved
Methodology
Chromosomal / Cytogenetics (FISH)
Biomarkers
Result Turnaround Time
7-10 days
Related Documents
For more information, please review the documents below
Specimen
Amniotic Fluid (Fresh)
Volume
20-30 cc
Minimum Volume
20 cc
Container
Two sterile 15 ml conical centrifuge tubes
Collection Instructions
Discard the first 2 cc of fluid collected.
Storage Instructions
Ship at room temperature
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Not specified |
| Refrigerated | Not applicable |
| Frozen | Not frozen |