Types of Testing
Diagnostic: confirm diagnosis in symptomatic patient (cystic fibrosis, Huntington). Predictive/presymptomatic: identify risk before symptoms (BRCA1/2, Huntington). Carrier: identify carriers of recessive conditions (cystic fibrosis, sickle cell, Tay-Sachs) — for family planning. Prenatal: amniocentesis (15-20 weeks), CVS (10-13 weeks), NIHT (cell-free DNA, 10+ weeks), carrier screening. Newborn screening: heel stick for metabolic, endocrine, hemoglobin disorders. Pharmacogenomic: drug response prediction (CYP2D6, HLA-B*5701). Whole exome/genome sequencing: comprehensive analysis.
Counseling Process
Pre-test: assess risk, reason for testing, family history (pedigree), informed consent (benefits, risks, limitations, implications), psychosocial readiness, support system. Test selection: appropriate test, lab, sample type. Post-test: result disclosure (in person for significant results), explain meaning, implications for patient and family, emotional support, medical management, family planning, cascade testing (testing relatives), resources. Non-directive: counselor provides information, patient makes decisions. Ethical: testing children for adult-onset conditions generally not recommended.
Nursing Role
Identify patients who may benefit from genetic testing (family history, early onset disease, ethnic predilection, multiple affected relatives). Educate: about testing options, process, implications. Facilitate referral to genetic counselor. Support patient decision-making. Coordinate testing logistics. Explain results (with genetic counselor). Assess understanding and emotional response. Support family communication. Advocate for privacy and non-discrimination. Integrate genetics into nursing assessment. Stay current: genetics is rapidly evolving. Resources: Genetics Home Reference, NSGC, GeneReviews, OMIM.
Important Notes
- Genetic testing of children for adult-onset conditions is generally NOT recommended — the child should decide as an adult.
- Genetic test results have implications for the ENTIRE family — cascade testing (testing at-risk relatives) is important.
Clinical Tips
- BRCA1/2 testing is predictive — informs risk management (enhanced screening, prophylactic surgery, chemoprevention) — not a diagnosis.
- Informed consent for genetic testing must include psychological, social, and insurance implications, not just medical risks.
Summary
Genetic testing requires pre-test counseling (risk assessment, consent, family history), appropriate test selection, post-test support, and cascade testing of at-risk relatives.
