Expanded Chromosomal Microarray Analysis - Prenatal - Amniotic Fluid
Use
Expanded Chromosomal Microarray Analysis (CMA) leverages advanced aCGH technology, utilizing 400K oligonucleotides for comprehensive copy number analysis of over 1,700 genes. It is designed for prenatal evaluations of potential chromosomal abnormalities, providing insightful data for managing pregnancies with abnormal ultrasound findings, prior chromosomal abnormalities, or high maternal age. Nevertheless, CMA is limited in detecting low-level mosaicism and certain balanced rearrangements, rendering it crucial for clinicians and families requiring detailed genetic assessment for informed decision-making regarding potential risks and management options. It is particularly beneficial for conditions such as uniparental disomy and consanguinity, with a focus on delivering the highest level of detection.
Special Instructions
A CMA consent signature is recommended and samples must be prepared according to established guidelines. It is crucial to conduct maternal cell contamination studies whenever maternal blood is collected. Paraent samples are essential for certain interpretations, which will be performed automatically when needed. Notably, specific results will necessitate parental studies without automatic performance, which will be billed as a separate service. Attention also needs to be given to alerts regarding results such as absence of heterozygosity, due to additional testing recommendations that might follow.
Limitations
CMA will not report gains and losses less than 1Mb, along with other limitations concerning clinically irrelevant changes or those associated with adult-onset disorders. These constraints ensure that clinically significant findings are prioritized and are articulated within guidelines specified by the American College of Medical Genetics. It is imperative to remain cognizant of these limitations during test interpretation to prevent any miscommunication at the points of care.
Methodology
Chromosomal / Cytogenetics (FISH)
Biomarkers
Result Turnaround Time
7-10 days
Related Documents
Not provided.
Specimen
Amniotic Fluid
Volume
20-30 cc
Minimum Volume
2 cc
Container
two sterile 15 ml conical centrifuge tubes
Collection Instructions
Discard the first 2 cc of fluid collected.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |