Faq

Genomic testing is a medical test that detects changes in genes, chromosomes, or proteins. It helps confirm or rule out a suspected genomic condition and can assess the likelihood of developing or passing on a genomic disorder. Over 77,000 genomic tests are available, with more in development.

Genomic testing examines:

• Genes: Tests analyze DNA sequences to detect mutations that may cause or increase the risk of genomic disorders. These tests can range from analyzing a single nucleotide to an entire genome.
• Chromosomes: Tests assess whole chromosomes or long DNA segments to identify large genomic changes, such as an extra chromosome, which could lead to a genomic condition.
• Proteins: Tests measure the amount or activity level of proteins or enzymes to detect abnormalities.

There are various genomic tests available to analyze changes in genes, chromosomes, or proteins. Health care providers select the appropriate test based on the suspected condition and the genomic variations typically linked to it.

• Molecular Tests: These tests analyze DNA sequences to detect genomic changes:
  • Targeted Single Variant: Looks for a specific variant in one gene.
  • Single Gene: Examines an entire gene for any mutations.
  • Gene Panel: Tests multiple genes for variants.

• Whole Exome/Genome Sequencing: Analyzes most of an individual’s DNA to find genomic variations, used when specific gene tests are inconclusive, or the genomic cause is unclear.

• Chromosomal Tests: Examine whole chromosomes or large DNA segments to identify significant genomic changes.

• Gene Expression Tests: Analyze which genes are active in cells by studying mRNA levels, helping to identify conditions like cancer based on gene activity.

• Biochemical Tests: Measure the amount or activity level of proteins or enzymes to infer genomic abnormalities.

Once a person decides to proceed with genomic testing, a healthcare provider can arrange it, often as part of a genomic consultation.

Genomic tests are performed on samples of blood, hair, skin, amniotic fluid, or other tissues. For example, a buccal smear uses a small brush or cotton swab to collect cells from the inside of the cheek.

Newborn screening involves pricking the baby’s heel to collect a small blood sample.

Individuals interested in direct-to-consumer genomic testing can obtain tests directly from the testing company, without needing a healthcare provider. However, those who test positive or are found to be at higher risk for a condition are encouraged to consult a genomic counselor or healthcare provider for further guidance.

Screening tests evaluate an individual’s risk of developing a genomic condition, while diagnostic tests identify genomic conditions. All genomic tests have both benefits and limitations.

Genomic screening tests are used in individuals without symptoms to estimate their risk of developing a condition compared to others in a similar population. A positive result indicates a higher-than-average risk, and a negative result suggests a lower-than-average risk. However, a positive result does not mean the individual has the condition. Since screening tests are estimates, they can produce false positives (indicating a risk when the person is unaffected) or false negatives (suggesting no risk when the person is affected). While not definitive, these tests can help determine if further diagnostic testing is needed.

Genomic diagnostic tests are typically used in individuals with signs or symptoms to confirm or rule out suspected genomic conditions. These tests can also assess the likelihood of developing or passing on a genomic disorder. The results help guide healthcare decisions and management of the condition.