Genetic testing — analysis of DNA to identify gene variants associated with disease risk, diagnosis, treatment response, or hereditary conditions — has moved from research laboratories into mainstream clinical medicine. Medical clinics now routinely offer genetic testing for cancer risk assessment, pharmacogenomics (how genes affect drug response), inherited disease diagnosis, and family planning. This guide explains what clinical genetic testing is, what it can reveal, and how to access it through your healthcare provider.
Types of Clinical Genetic Tests
Hereditary Cancer Risk Testing
Testing for BRCA1/2 mutations (breast and ovarian cancer risk), Lynch syndrome (colorectal cancer risk), and panels covering multiple cancer-associated genes identify patients with significantly elevated cancer risk who benefit from intensified screening, prophylactic surgery, or chemoprevention. Genetic counseling before and after testing helps patients understand results and implications.
Pharmacogenomics
Genetic variants in drug-metabolizing enzymes (CYP2D6, CYP2C19, TPMT, and others) affect how patients metabolize specific medications — influencing dosing requirements, effectiveness, and side effect risk. Pharmacogenomic testing informs prescribing for antidepressants, antipsychotics, opioid pain medications, and many other drugs. Results stored in the EHR provide guidance for future prescribing decisions.
Carrier Testing
Preconception or prenatal carrier testing identifies whether prospective parents carry one copy of genes for recessive genetic conditions (cystic fibrosis, sickle cell disease, spinal muscular atrophy) — determining the chance of passing the condition to children.
Diagnostic Genetic Testing
When a genetic condition is suspected based on clinical features, diagnostic testing identifies the specific genetic cause — informing prognosis, management, and family implications.
Genetic Counseling
Genetic counseling — provided by certified genetic counselors — is an essential companion to genetic testing, helping patients understand what testing involves, what results mean, psychological implications of findings, and implications for family members. Many clinics have genetic counselors on staff or can provide referrals.
Conclusion
Genetic testing at the clinical level provides information that genuinely changes medical management — from cancer surveillance intensification to medication dosing optimization to family planning decisions. If you have a personal or family history that might benefit from genetic evaluation, discuss testing with your clinic and request genetic counseling to ensure you fully understand the implications of any results.
FAQs – Genetic Testing
Q1. Is genetic testing covered by insurance?
A: Coverage varies. Testing with a clear clinical indication (positive family history, diagnostic evaluation) is more likely to be covered. Expanded carrier screening and pharmacogenomics coverage varies significantly by plan. Prior authorization is often required for genetic testing.
Q2. Does a positive BRCA test mean I will definitely get cancer?
A: No. BRCA1 mutations confer a lifetime breast cancer risk of approximately 65–72% and ovarian cancer risk of 39–46%. These are substantially elevated risks but not certainties — many BRCA mutation carriers never develop cancer. Risk management strategies (enhanced surveillance, prophylactic surgery, chemoprevention) substantially reduce the risk.
Q3. What is direct-to-consumer genetic testing?
A: Services like 23andMe and AncestryDNA provide consumer genetic information on ancestry, traits, and limited health risk assessment. These are not clinical tests — they use different technologies and are not validated for medical decision-making. Clinical genetic testing ordered by a provider is appropriate for medical decisions.
Q4. Who should consider BRCA testing?
A: BRCA testing is recommended for individuals with personal or family history of breast cancer (particularly early-onset, bilateral, or in men), ovarian cancer, Ashkenazi Jewish ancestry with any cancer history, or multiple cancers in close relatives. USPSTF guidelines specify criteria for referral.
Q5. Can I be discriminated against based on genetic test results?
A: The Genetic Information Nondiscrimination Act (GINA) prohibits genetic discrimination in health insurance and employment. It does not cover life insurance, disability insurance, or long-term care insurance. Understanding these protections and their limits is part of the genetic counseling process.
