Understand the Difference between Genetic Testing and Genomic Sequencing


Let’s start with a quick biology review.

Every cell in the human body contains individual units of heredity called genes. Genes are basically instructions that tell cells how to behave. A person’s eye color, height, and facial features are controlled by genes. A person has two copies of each gene—one gene from each parent.


Genetic testing can be done on any cell in the body to look for bad genes (mutations) that were carried by either parent’s germ cell (egg or sperm). A mutation that is inherited is called a germline mutation. Genetic testing looks for germline mutations.


A mutation that happens to a cell after fertilization is called a somatic mutation. Somatic mutations can happen spontaneously or as a result of exposure to substances like tobacco smoke, radiation, or hazardous chemicals. Somatic mutations can be identified by looking at various genes from a cancerous tumor. This process is called genomic sequencing.

Whole genome sequencing looks at all of the 20,000 genes in the body (human genome). Targeted gene sequencing examines a subset of 100-500 genes most likely to have been mutated. Both methods are enabled by a technique called Next Generation Sequencing.  Medications that focus on a specific mutation are called targeted therapies.

So the take away message is: genetic testing is used to look for inherited mutations in healthy cells and genomic sequencing is used to look at genetic mutations in unhealthy cells.

Intermountain Healthcare Precision Genomics personalizes treatment for cancer by testing for all types of genetic mutations. The ICG 100 test offers genetic testing for patients who have failed traditional standard of care treatment options.

To learn more about Intermountain Precision Genomics and this type of personalized medicine, visit: precisioncancer.org.