Test Code LAB9096 Panel Refelex to Exome Analysis
Aliases
Germline testing
Performing Section
PRECISION DIAGNOSTICS
Specimen Type
Whole Blood/Purple Top Tube (K2 EDTA) or Buccal Swab.
Specimen Volume
- Optimal Volume: 4.0 ml
- Minimum Volume: 0.5 ml
Processing Instructions
If transport is longer than 4 hours send on cold pack
TAT
5 weeks
CPT
Proband Only – 81415
Duo Analysis – 81415
Trio Analysis – 81416
Special Collection Notes
Collect specimen according to standard operating procedure
Additional Notes
The diagnostic yield of whole exome sequencing tests ranges from 25%-42%. The yield is lower in proband only cases as compared to trio analyses. The phenotype of the individual being tested also impacts the yield. Phenotypes such as autism spectrum disorder can have a yield between 6-15% while well-phenotyped pediatric epilepsies can yield a diagnoses in up to 40% of cases. The exome wide testing also enables delineation of complex phenotypes caused by more than one genetic defect (dual molecular diagnoses) ranging from 1% in skeletal diseases to 5-7% in phenotypes such as ataxia, multiple congenital anomalies, and epilepsy
Method
Next Generation Sequencing
Purpose/Principle
The CHCO Whole Exome Sequencing (WES) test utilizes next-generation sequencing technology. The assay interrogates the coding regions and flanking intronic bases of the cited genes, with the capacity to detect sequence variants, copy number variants (CNVs), and mitochondrial variants. Uniform genomic coverage is achieved through standardized specimen processing and short-read sequencing. Sequencing data are monitored by quality control metrics to ensure high confidence in the accuracy and specificity of the variant calls. The CNV resolution threshold is approximately 1 Mb, although smaller events may be detected depending on regional complexity and data quality.