Genetic testing can be uniquely different from other laboratory tests. One difference is that often it is useful for the laboratory to have information about the patient or family history for interpretation of test results. Gathering the appropriate clinical information and a complete family history is not always straightforward and needs to be tailored to the specific test being offered. A genetic counselor is uniquely trained to understand and interpret the appropriate information needed by the molecular pathology laboratory in order to perform a specific genetic test. Oftentimes it can be challenging to work within a family system to get the necessary information to document a
Table 3-3. Genetic Counselors Working with the Molecular Pathologist
Obtain clinical information and family history data to ensure that the most appropriate test is performed Facilitate the informed consent process to assure that the patient's autonomy is protected Interpret clinical validity and test results for referring physicians and patients genetic diagnosis prior to testing at-risk individuals. For example, if a patient presents requesting testing for spinocerebellar ataxia (SCA) because this condition has been diagnosed in a sibling, it is important to know the specific type of SCA, as there are currently 17 types and commercial testing is available for only about 7 of the 17. If the individual requesting the test does not know the type, one could do testing for all of the commercially available types; however, a negative result would not absolve the individual at risk because the proband may have one of the SCAs not included in the testing. A genetic counselor can work with an at-risk individual to obtain the necessary family history information and documentation so that the most accurate and efficient approach to testing can be used and the interpretation of the results will be more informative. An accurate and comprehensive family history is a valuable tool in a diagnostic evaluation as it can be used as a medical screening tool, establish a pattern of inheritance, identify individuals at-risk, and determine strategies for genetic testing.
Understanding the clinical validity of a genetic test result can be difficult for both healthcare providers and patients. However, information about the sensitivity of the test and the penetrance of mutations is paramount to the interpretation of test results.9 Each genetic test has its own sensitivity and specificity based on the methodologies and technologies employed by the laboratory performing the test. Many laboratories have genetic counselors on staff. The genetic counselor can be a useful resource for the molecular pathology laboratory to interface with other healthcare providers and the public to provide the necessary education and information to determine the appropriate approach to genetic testing, facilitate the details of ordering a test, and help interpret test results (Table 3-3).
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