Targeted Chromosomal Microarray Analysis - Prenatal - Amniotic Fluid

Casandra

Casandra Test Code BA73769Version 1 (DRAFT)

Performing Lab

Lab Baylor GeneticsLab Test ID 8656CPT Codes 81265, 81288

Targeted Chromosomal Microarray Analysis - Prenatal - Amniotic Fluid

Clinical Use

Use

CMA-Targeted is a prenatal diagnostic tool designed to detect chromosomal abnormalities through advanced genomic analysis. This test utilizes aCGH technology with 180,000 oligonucleotides, focusing on chromosomal areas associated with common deletion and duplication syndromes. It is indicated for patients with prenatal ultrasound abnormalities, positive noninvasive prenatal testing, or those with increased age-related risks. While it effectively identifies many clinically significant genomic disorders, the test lacks the capacity to detect low-level mosaicism, balanced translocations, and specific gene mutations, thus making it essential to interpret results within the patient's broader clinical context.

Special Instructions

For successful testing, a signed CMA consent is recommended. Parental samples (5 cc whole blood in EDTA) are required, and maternal cell contamination studies will be performed for each case where maternal blood is included. Parental studies will only be conducted under specific circumstances, such as for heterozygous gains or losses linked to autosomal recessive disorders and further tests for unbalanced rearrangements, which will incur additional costs. Baylor Genetics will also notify clients of relevant findings from AOH results and provide testing recommendations where appropriate.

Limitations

The analysis will not report gains and losses below 1Mb or those with low clinical relevance, including specific gene-associated gains. Furthermore, changes in the mitochondrial genome and adult-onset disorder-related gains are excluded from reporting. This is a fundamental limitation when utilizing CMA for prenatal analysis, as the focus remains strictly on clinically actionable results primarily associated with known syndromes. Results indicating balanced arrangements and point mutations are also out of scope for this test, emphasizing the need for clinical correlation when interpreting findings.

Test Details