8.5 Unit Summary and Review

Genetic testing analyzes DNA, genes, chromosomes, or proteins to identify changes associated with health conditions. It serves various purposes, including predicting disease risk, identifying carriers of genetic conditions, diagnosing disorders, guiding treatment decisions, and informing research. Examples include newborn screening, prenatal testing, carrier screening, pharmacogenomic testing, and diagnostic tests. The benefits include reducing uncertainty about health risks, guiding preventive measures, and aiding treatment planning. However, testing has limitations, such as emotional, financial, and social implications, potential discrimination, and gaps in actionable treatments for identified disorders. Nurses play a critical role in patient education, informed decision-making, and coordination with genetic counsellors.

Genomic testing is becoming more accessible and integrated into primary care, yet its complexity raises challenges, particularly around interpreting results. Canadian laboratories typically classify genomic variants into five categories—pathogenic, likely pathogenic, variant of uncertain significance (VUS), likely benign, and benign—using guidelines like those from the American College of Medical Genetics and Genomics (ACMG). Misinterpreting results can lead to unnecessary follow-up, improper clinical management, or false reassurance. Secondary findings, unrelated to the primary reason for testing but may provide actionable health insights, are increasingly reported in whole exome and genome sequencing. However, they can also pose ethical and emotional challenges. Pre- and post-test counselling is essential to help individuals understand the implications of these findings and plan for their medical care.