Genetic testing may sometimes be referred to as just one category, though there are several subcategories used to differentiate different genetic tests.
Identifies people who may be carriers of a genetic disorder.
Carrier testing is performed to identify individuals who have a gene mutation for a disorder inherited in an autosomal recessive or X-linked recessive manner. Carriers usually do not themselves have symptoms related to the gene mutation. Carrier testing is offered to individuals who have family members with a genetic condition, family members of an identified carrier, and individuals in ethnic or racial groups known to have a higher carrier rate for a particular condition.
Points to consider:
For individuals with symptoms and a family history of geneti
For individuals with symptoms and a family history of genetic disorders.
Diagnostic testing is used to confirm or rule out a known or suspected genetic disorder in a symptomatic individual.
For individuals with no symptoms but with a family history o
For individuals with no symptoms but with a family history of genetic disorders.
Predictive testing is offered to asymptomatic individuals with a family history of a genetic disorder. Predictive testing is of two types: presymptomatic (eventual development of symptoms is certain when the gene mutation is present, e.g., Huntington disease) and predispositional (eventual development of symptoms is likely but not certain when the gene mutation is present, e.g., breast cancer).
Points to consider:
Prenatal testing is performed during a pregnancy to assess t
Prenatal testing is performed during a pregnancy to assess the health status of a fetus. Prenatal diagnostic tests are offered when there is an increased risk of having a child with a genetic condition due to maternal age, family history, ethnicity, or suggestive multiple marker screen or fetal ultrasound examination. Routine prenatal diagnostic procedures are amniocentesis and chorionic villus sampling (CVS). More specialized procedures include placental biopsy, periumbilical blood sampling (PUBS), and fetoscopy with fetal skin biopsy.
Genetic testing for embryos resulting from in vitro fertiliz
Genetic testing for embryos resulting from in vitro fertilization.
Preimplantation testing is performed on early embryos resulting from in vitro fertilization in order to decrease the chance of a particular genetic condition occurring in the fetus. It is generally offered to couples with a high chance of having a child with a serious disorder. Preimplantation testing provides an alternative to prenatal diagnosis and termination of affected pregnancies.
GeneTests was created to simplify the search for genetic tes
GeneTests was created to simplify the search for genetic testing laboratories, which may be difficult to locate. For many diseases, there may be only one laboratory providing genetic testing. U.S. patents have been issued covering diagnostic testing for some genetic disorders. A given laboratory may or may not be the exclusive licensee to such a patent. If there is a choice of laboratories, the following factors should be considered:
Genetics laboratory personnel have two major roles: processing patient samples (technologists), and interfacing with referring clinicians regarding their patients (clinical consultants). Lab personnel, who are usually certified in their specialty, may include lab directors, supervisors, technologists, and genetic counselors.
Compatibility: The test offered by the laboratory must match the specific clinical need
Reliability: Direct contact with the laboratory is needed to assess the laboratory's experience and qualifications
Ease of Communication
Turn-Around Time: Time from sample receipt to test result report may vary
Cost: May vary from less than $100 to more than $2000 based on several factors
If genetic testing is clinically available and useful for a ...
If genetic testing is clinically available and useful for a particular patient, the patient needs to understand why it is being offered and its implications for medical management and psychosocial well-being. If a competent patient (or parent/guardian) agrees to the proposed genetic test after full disclosure, this constitutes informed consent. Informed consent may be verbal or written. Some laboratories require written documentation of informed consent. (See sample informed consent form from CompGene.)
Pretest counseling includes:
Results should be revealed only to the individual tested, or his/her parent or guardian, unless explicit permission has been granted to share results.
Additional issues relevant in some testing situations:
Contact the lab directly to ask the following questions:
What are the sample requirements?
What supporting documentation is needed?
How should the sample be transported?
Test results are provided in writing by the laboratory to th
Test results are provided in writing by the laboratory to the referring clinician. The details of the lab report vary by lab, but may include:
The clinician explains the meaning of the test result to the patient and to other family members as needed. Test results and follow-up should be documented in the medical record and a copy made available to the patient. For many conditions, educational materials may be available from patient support organizations.
Parent support & information: