Genetic Testing for Cystic Fibrosis
DESCRIPTION
Genetic tests involve the analysis of human DNA, RNA, chromosomes, proteins and certain metabolites. These tests are used to detect certain hereditary diseases. When used in the clinical setting, these tests can be used to predict risk of disease, identify carriers, and formulate prenatal diagnosis/prognosis. Cystic fibrosis (CF) is an inherited autosomal recessive disease of the exocrine glands associated with a high morbidity and early mortality. It is characterized by abnormal chloride transport across cell membranes causing dehydrated secretions. This leads to tenacious mucus in the lungs and to mucus plugs in the pancreas.
The CF gene, CF transmembrane conductance regulator (CFTR), is located on chromosome 7. The CFTR gene produces a protein that helps transport chloride ions across cell membranes. There are approximately 600 mutations of the CFTR gene, but the most prevalent one is called delta F508. Approximately 70% of individuals with CF have this mutation, which lacks a single amino acid in its protein, making it nonfunctional.
With an autosomal recessive disorder both parents must carry some form of the gene mutation for cystic fibrosis in order to have an affected offspring. Therefore, dual carrier parents will have a 25% chance of having an affected child, a 25% chance of having an unaffected child, and a 50% chance of having a carrier child.
POLICY
Genetic testing for cystic fibrosis to determine the carrier status of an individual is considered medically necessary if the medical appropriateness criteria are met. (See Medical Appropriateness below.)
Genetic testing for cystic fibrosis for diagnostic purposes is considered medically necessary if the medical appropriateness criteria are met. (See Medical Appropriateness below.)
Pre- and post- genetic counseling as an adjunct to genetic testing itself is considered medically necessary.
Genetic testing for cystic fibrosis for use in mass screening and routine screening of newborns is considered investigational.
MEDICAL APPROPRIATENESS
Genetic testing for cystic fibrosis to determine carrier status is considered medically appropriate for individuals if ANY ONE of the following criteria are met:
Adults with a positive family history of cystic fibrosis
Partners of individuals with cystic fibrosis who are planning a pregnancy
Couples seeking prenatal care
Genetic testing for cystic fibrosis for diagnostic purposes is considered medically appropriate for individuals if ALL of the following criteria are met:
A clinical presentation consistent with cystic fibrosis
A negative sweat chloride test
Note: Genetic counselors must be licensed, certified, or eligible for board certification in their profession, and must have specific training in cancer genetics. Counselors must also be a member of a national genetics society or a national oncology society.
IMPORTANT REMINDER
We develop Medical Policies to provide guidance to Members and Providers. This Medical Policy relates only to the services or supplies described in it. The existence of a Medical Policy is not an authorization, certification, explanation of benefits or a contract for the service (or supply) that is referenced in the Medical Policy. For a determination of the benefits that a Member is entitled to receive under his or her health plan, the Member's health plan must be reviewed. If there is a conflict between the Medical Policy and a health plan, the express terms of the health plan will govern.
ADDITIONAL INFORMATION
Laboratories that conduct genetic testing must comply with the provisions of the Clinical Laboratory Improvement Act (CLIA), which is administered by the Center for Medicare and Medicaid services (CMS) and Centers for Disease Control (CDC).
Diagnosis of CF is generally confirmed by means of sweat chloride testing and does not require documentation of genetic mutation. However, in cases of clinically suspected CF, in which sweat chloride values are normal or non-diagnostic, documentation of CF mutation on both chromosomes is sufficient to confirm a diagnosis.
Published data is inadequate to permit conclusions regarding the use of genetic testing for cystic fibrosis for the purpose of mass screening or routine screening of newborns.
SOURCES
American Medical Association. ((2011). Cystic fibrosis testing. Retrieved July 18, 2011 from http://www.ama-assn.org/ama/pub/physician-resources/medical-science/genetics-molecular-medicine/related-policy-topics/genetic-testing/cystic-fibrosis-testing.page#.
American College of Obstetricians and Gynecologists Committee on Genetics. (2011). ACOG committee opinion No. 486: Update on carrier screening for cystic fibrosis. Obstetrics and Gynecology, 117 (4), 1028-1031.
Brice, P., Jarrett, J., & Mugford, M. (2007). Genetic screening for cystic fibrosis: An overview of the science and the economics. Journal of Cystic Fibrosis. 6 (4), 255-261.
Cavanagh, L., Compton, C. J., Tluczek, A., Brown, R. L., & Farrell, P. M. (2010). Long-term evaluation of genetic counseling following false-positive newborn screen for cystic fibrosis. Journal of Genetic Counseling, 19 (2), 199-210.
Chen, B., Gagnon, M., Shahangian, S., Anderson, N. L., Howerton, D. A., Boone, J. D., et al. (2009). Good laboratory practices for molecular genetic testing for heritable diseases and conditions. MMWR. Recommendations and reports: Morbidity and mortality weekly report, 58 (RR-6), 1-37.
Dungan, J. S. (2010). Carrier screening for cystic fibrosis. Obstetrics & Gynecology Clinics of North America, 37 (1), 47-59.
Farrell, P. M., Rosenstein, B. J., White, T. B., Accurso, F. J., Castellani, C., Cutting, G. R., et al. (2008). Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consensus report. Journal of Pediatrics, 153 (2), S4-S14.
Goetzinger, K. R., & Cahill, A. G. (2010). An update on cystic fibrosis screening. Clinics in Laboratory Medicine, 30 (3), 533-543.
LeGrys, V. A., Yankaskas, J. R., Quittell, L. M., Marshall, B. C., & Mogayzel, P. J. (2007). Diagnostic sweat testing: The Cystic Fibrosis Foundation guidelines. The Journal of Pediatrics, 151 (1), 85-89.
Lindau-Shepard, B. A. & Pass, K. A. (2010). Newborn screening for cystic fibrosis by use of a multiplex immunoassay. Clinical Chemistry, 56 (3), 445-450.
National Guideline Clearinghouse. (2011, January). Genetic considerations for a woman’s pre-conception evaluation. Retrieved July 18, 2011 from http://www.guidelines.gov.
National Guideline Clearinghouse. (2010). The optimal evaluation of the infertile male: AUA best practice statement. Retrieved July 18, 2011 from http://www.guidelines.gov.
Pratt, V. M., Caggana, M., Bridges, C., Buller, A. M., DiAntonio, L., Highsmith, W. E., et al. (2009). Development of genomic reference materials for cystic fibrosis genetic testing. The Journal of Molecular Diagnostics, 11 (3), 186-193.
Strom, C. M., Janeszco, R., Quan, F., Wang, S. B., Buller, A., McGinniss, M., et al. (2006). Technical validation of a TM Biosciences Luminex-based multiplex assay for detecting the American College of Medical Genetics recommended cystic fibrosis mutation panel. The Journal of Molecular Diagnostics, 8 (3), 371-375.
Wei, S., Quigg, M. H., & Monaghan, K. G. (2007). Is cystic fibrosis carrier screening cost effective? Community Genetics, 10 (2), 103-109.
ORIGINAL EFFECTIVE DATE: 6/1999
MOST RECENT REVIEW DATE: 8/11/2011
ID_BT
Policies included in the Medical Policy Manual are not intended to certify coverage availability. They are medical determinations about a particular technology, service, drug, etc. While a policy or technology may be medically necessary, it could be excluded in a member's benefit plan. Please check with the appropriate claims department to determine if the service in question is a covered service under a particular benefit plan. Use of the Medical Policy Manual is not intended to replace independent medical judgment for treatment of individuals. The content on this Web site is not intended to be a substitute for professional medical advice in any way. Always seek the advice of your physician or other qualified health care provider if you have questions regarding a medical condition or treatment.
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