A genetic test is the analysis of human DNA, RNA, chromosomes, proteins, or certain metabolites in order to detect alterations related to a heritable disorder. This can be accomplished by directly examining the DNA or RNA that makes up a gene (direct testing), looking at markers co-inherited with a disease-causing gene (linkage testing), assaying certain metabolites (biochemical testing), or examining the chromosomes (cytogenetic testing).

Although genetic testing shares some features in common with other kinds of laboratory testing, in many ways it is unique and requires special considerations.

Points to consider:

  • Genetic testing may be used for medical management and for personal decision-making.
  • Genetic test results usually apply not only to the patient but also to other family members.
  • Genetic testing may be performed in the context of a genetics consultation and should include informed consent, test interpretation, and follow-up medical and psychosocial services as indicated.
  • Because most genetic disorders are rare, genetic testing is often done only by specialized laboratories.
  • Intense research efforts in molecular genetics result in the rapid development and availability of new genetic tests; therefore, healthcare providers need to continuously update their knowledge.
  • In order for genetic testing to yield meaningful results:
    • multiple test methodologies may be required
    • other family members may need to be tested
    • a genetics consultation may be appropriate

These services will entail additional costs.

What is a Clinical Test?

Clinical tests are those in which specimens are examined and results reported to the provider or patient for the purpose of diagnosis, prevention, or treatment in the care of individual patients.

Points to consider:

  • United States laboratories performing clinical tests must be CLIA approved (certified by the national certification process). In order to be CLIA approved, a laboratory must meet quality control and proficiency testing standards.
  • There is a charge for clinical tests; cost varies by complexity.
  • Test results are reported in writing.
  • The time between specimen submission and reporting of results varies between laboratories and may be based in part on the complexity of the testing.

What is a Research Test?

Research tests are those in which specimens are examined for the purpose of understanding a condition better, or for developing a clinical test.

Points to consider:

  • Laboratories performing research testing are not subject to CLIA regulation.
  • The cost of research testing is generally covered by the researcher.
  • Test results are generally not given to patients or their providers.
  • Rarely, a research laboratory will, at the patient’s request, share potentially useful findings with a clinical laboratory so the patient’s test results can be confirmed and a formal report issued.
  • Requests for participation in research may be denied, at the laboratory’s discretion, if the laboratory has sufficient samples or the family does not fit the research project goals.

What is an Investigational Test?

Investigational tests are deemed to be of value but not yet scientifically valid or generally accepted by the medical community as accurate and useful.

Points to consider:

  • Test results may or may not be shared, and it may be a long time before results are available.
  • If test results are shared with the provider or patient, the laboratory must be CLIA approved.
  • There may or may not be a cost for testing.

GeneTests: Medical Genetics Information Resource (database online). Educational Materials: About Genetic Services. Copyright, University of Washington, Seattle. 1993-2006. Available at http://www.genetests.org. Accessed January 5, 2006.