Ordering molecular genetic tests: Clinician considerations and precautions

INTRODUCTION

Molecular genetic testing is increasingly integrated into clinical care, with applications in rare diseases, hereditary cancer syndromes, pharmacogenomics, and precision oncology. These technologies can identify pathogenic variants, guide therapeutic strategies, and stratify familial disease risk. However, indiscriminate or poorly informed use may lead to false reassurance, unnecessary anxiety, increased cost, or misinterpretation. Furthermore, the regulatory environment particularly concerning laboratory-developed tests, next-generation sequencing assays, and circulating tumor DNA, continues to evolve, necessitating caution and updated clinician knowledge.

PRE-ORDER CONSIDERATIONS

TEST ORDERING AND SPECIMEN HANDLING (PRE-ANALYTIC PHASE)

Accurate requisition forms should capture clinical context, family history, ethnicity, and patient consent. Specimen quality is critical – sample type, collection, transport, and storage must follow laboratory-specific protocols. Institutions employing utilization management strategies (e.g., pre-test review by genetic counselors) have reported cost saving and improved appropriateness.^[4]

ANALYTIC AND LABORATORY QUALITY

Laboratory transparency regarding analytical sensitivity, specificity, coverage, and assay limitations is essential. For pathogenic variants, sensitivity should exceed 99%. Accreditation frameworks (e.g., CLIA and CAP) require quality control, equipment validation, and proficiency testing to ensure reliability.^[1,3]

POST-ANALYTIC REPORTING AND RESULT INTERPRETATION

• Standardized reporting: Clear, template-based reports – with bolded key findings, actionable recommendations, and clinical follow-up steps – improve interpretation by non-specialist physician.^[5]

• Multidisciplinary review: Variant interpretation benefits from collaboration among geneticists, pathologists, and clinicians, with approximately 14% of cases showing discrepancies between laboratory and clinical classification.

• VUS management: Patients should understand that VUS is not actionable. Periodic reclassification and family segregation studies may clarify significance.

• Secondary findings: In WES/WGS, discussion of optin/opt-out policies for actionable secondary findings (e.g., American college of medical genetics, secondary findings [ACMG SF] v3.0 gene list) must occur during informed consent.

• Follow-up: Reports should provide interpretation, management recommendations, and laboratory contact details. Retention of reports is advised for at least 10 to 25 years.

• Always seek a Medical Geneticist opinion/consultation.

ETHICAL, LEGAL, AND COUNSELING CONSIDERATIONS

• Autonomy and consent: Shared decision making is vital, especially as evidence and recommendations evolve.^[6]

• Confidentiality and privacy: Clinicians must ensure proper consent for data use, storage, and disclosure, with compliance to legal frameworks such as Genetic Information Nondiscrimination Act of 2008 (GINA) in the United States of America (U.S.A) although no equivalent legal framework currently exist in India.^[7]

• Familial implications: Germline test results may necessitate cascade testing. Clinicians should encourage communication with relatives while respecting autonomy.

• Reinterpretation and recontact: International guidelines differ. In Canada, shared responsibility among clinicians, laboratories, and patients is recommended.^[8] India currently lacks such guidance, requiring clinician-laboratory improvisation.

• Equity and justice: Barriers to access including cost, geography, and cultural factors should be addressed to ensure equitable availability.

POPULATION AND ELECTIVE TESTING

Direct-to-consumer and elective testing may reveal health risks or ancestry information, but often lack clinical validity. Physicians should caution patients about over interpretation and encourage confirmatory clinical testing. Legal protections against genetic discrimination (e.g., GINA in the U.S.A) do not extend to life or disability insurance and are absent in India, leaving patients potentially vulnerable.

EMERGING TECHNOLOGIES AND FUTURE DIRECTIONS

Artificial intelligence (AI)-integrated molecular diagnostics such as digital PCR and isothermal amplification promise enhanced sensitivity and point-of-care applicability. However, expanding use of genomic and health data necessitates stronger governance frameworks for privacy, equity, and discrimination protections.^[9]

PRACTICAL CHECKLIST FOR CLINICIANS

1. Confirm clinical indication and utility

2. Provide pre-test Medical Genetic consultation, counseling and obtain informed consent

3. Collect detailed three-generation pedigree information

4. Select an appropriate test type and an accredited laboratory.

5. Complete requisition with clinical context and consent

6. Ensure specimen quality and integrity

7. Verify laboratory quality control and validation

8. Interpret results through standardized reports and multidisciplinary review

9. Communicate findings clearly to patients. Provide post-test medical genetic consultation and counseling

10. Plan cascade testing where relevant

11. Monitor for reclassification of VUS and plan recontact

12. Document rationale, consent, and reports in patient records.

13. Always seek Medical Geneticist opinion for optimal results

CONCLUSION

Ordering molecular genetic tests requires balancing scientific capability with clinical responsibility. Judicious test selection, robust counseling, meticulous specimen handling, and multidisciplinary interpretation are critical to maximize benefit and minimize harm. As technologies advance and data-sharing expands, clinician education, patient-centered Counseling and consent, and governance frameworks must evolve in parallel to ensure safe, ethical, and effective integration of molecular genetics into healthcare.