Panel vs Exome Testing: What’s the Difference and Which Should You Choose?

If you’ve ever wondered whether to order a genetic panel test or go straight for an exome, you’re not alone. One of the most common questions we get from clinicians is:

“What’s the difference between NGS panel testing and exome sequencing?”
“Can I find all panel genes in an exome test?”

Here’s the one-line answer:

Exome sequencing includes all panel tests.

Panel and Exome Tests Both Use NGS—So What’s the Real Difference?

Both panel testing and exome sequencing are based on Next-Generation Sequencing (NGS) technology. The key difference lies in scope:

• Panel Testing: Targets specific genes related to a suspected disorder.
• Exome Sequencing: Analyzes all protein-coding regions (exons) of the genome—roughly 20,000 genes.
• Genome Sequencing: Includes both coding and non-coding regions across the entire genome.

So, while panels are focused, exomes are comprehensive.

Why Panels Were the Standard—And What’s Changed

Traditionally, when a specific condition was suspected (e.g., epilepsy or cardiomyopathy), clinicians selected a pre-built panel containing genes associated with that condition.

But here’s where it got complicated:

• What if the gene of interest wasn’t included in the panel?
• What if a new gene is later found to be associated?
• Do you need to order another panel and explain another test to the patient?

This process can delay diagnosis and increase costs—not to mention add stress for clinicians and families alike.

Why Exome Sequencing Is Replacing Genetic Panel Testing in Rare Disease Diagnosis

Exome testing removes the guesswork.
Instead of choosing the “right” panel, you can start with the full picture—all genes, all at once.

At 3billion, our enhanced exome test goes even further by also including:

• Mitochondrial DNA coverage, and
• Key noncoding variants that are known to be clinically significant.

This means you’re not only replacing panel tests, you’re gaining greater diagnostic power in a single test.

“Think of exome sequencing as a super-panel—it already includes all the panels you’re considering, plus more.”

Customization Approach for Enhanced Exome Sequencing Coverage

“Exome Boosting by 3billion” addresses the limitations through a customized exome capture probe design to augment coverage in several key areas.

• Coding Exons with Insufficient Coverage: By addressing the insufficiencies in exon coverage, 3billion’s Enhanced Exome significantly enhances the reliability and comprehensiveness of genetic diagnostics, ensuring that critical pathogenic variants are noticed. For instance, the ORF15 exon of the RPGR gene is a well-known drop-out region in standard exome sequencing, often resulting in insufficient coverage and a higher risk of missing pathogenic variants. The RPGR gene is associated with several severe ocular conditions, including retinitis pigmentosa, cone-rod dystrophy, and macular degeneration. In the original 3B-EXOME, the coverage could be more sparse and consistent. In contrast, the Enhanced 3B-EXOME provides comprehensive and uniform coverage across the entire ORF15 exon, ensuring reliable detection of any pathogenic variants present.
• Non-coding Regions: In the enhanced version, additional capture baits have been added across non-coding regions that harbor disease-causing variants. This results in significantly improved coverage and detection capabilities for these non-coding regions, as illustrated by the more comprehensive and consistent read depth in the enhanced 3B-EXOME compared to the original. Regular updates to the capture bait design ensure newly identified non-coding variants are also targeted, providing a more comprehensive diagnostic tool.
• Mitochondrial Genome: In the enhanced version of 3billion’s exome testing, the coverage of the mitochondrial genome has been significantly increased. This integration within the exome sequencing process eliminates the need for separate mtDNA tests, which can be time-consuming and costly and ensures that mitochondrial variants are detected alongside nuclear DNA variants without additional procedures. For further details, please refer to the comprehensive article on Enhanced WES.

In conclusion, this enhanced exome sequencing from 3billion significantly improves the reliability and comprehensiveness of genetic diagnostics, ensuring critical pathogenic variants are detected. Experience the future of genetic testing with 3billion’s Enhanced Exome Sequencing and ensure no pathogenic variant goes undetected—contact us today to learn more.