Whole Exome Sequencing – Proband Only, Products of Conception (POC)

Casandra

Casandra Test Code LC35801Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 630999CPT Code 81415

Whole Exome Sequencing – Proband Only, Products of Conception (POC)

Clinical Use

Use

WES is currently intended for use by patients suspected to have a genetic disorder. While the test is most frequently ordered for patients who have been unable to obtain a definitive diagnosis through traditional genetic testing, physicians may opt to initiate whole exome sequencing earlier in the diagnostic pathway. An initial workup using whole exome sequencing may be especially useful when a multigene testing approach is desired but would be prohibitively time-consuming, or when a known genetic disorder is suspected but testing for the genes of interest is not available. Patients with atypical presentation of a suspected syndrome may be candidates for exome sequencing. While patients can be of any age, many of the patients with the most pressing need for exome-wide interpretation are children with serious childhood genetic diseases. TRIO testing consists of a proband or patient sample, and both biological parents. In the case both parents are not available for testing, up to two family member samples are also accepted. TRIOs are preferred for better diagnostic sensitivity.

Special Instructions

All test orders for WES require prior authorization review. MCC testing is mandatory for fetal samples, and the presence of MCC will result in test cancellation. Maternal blood should be submitted separately and fetal samples must use specific transport media. Contact genetic coordinators at 800-345-4363 before submitting a fetal sample.

Limitations

The assay cannot detect all genetic variants, such as low-level heteroplasmic mtDNA variants, large mtDNA deletions, or mosaicism. It may miss copy number variations, trinucleotide repeat expansions, epigenetic effects, large chromosomal rearrangements, or variants in repetitive or low-coverage regions. Sensitivity for detection of insertions and deletions is lower than for base substitutions. Findings may not impact clinical management, including therapeutic decisions or outcomes. It is not FDA approved or cleared.

Test Details

Methodology

NGS (WES)

Biomarkers

Comprehensive genomic profiling using Whole Exome Sequencing provides a detailed analysis of exons in the human genome, critical for identifying genetic variants associated with disease.