Cystic Fibrosis

Lab studies request form | CPT Codes/Price List (PDF)

CF is a common autosomal recessive disorder that affects many functions of the body such as respiration, endocrine function, and reproduction. CF worsens with age and affects both males and females. Although great strides in treatment have increased the length and quality of life for CF patients, it is nearly always fatal by the fourth decade of life. Sweat chloride testing remains the gold standard for diagnosis of CF, however DNA analysis is indicated not only for CF patients but also for their extended families. In addition to providing information about the specific mutations that cause CF, molecular testing allows rapid detection of cystic fibrosis carriers and can determine if the patient has a pancreatic sufficient or insufficient type of the disease. This information plays a large role in clinical management of the affected individual. Over 800 mutations have been described in the CF gene. However, screening for the 33 most common mutations detects ~90% of the mutant alleles in a population of Northern European ancestry. The carrier rates of the disorder are 1/25 Caucasians, 1/60 African-Americans, 1/46 Hispanics, 1/90 Asians, and 1/29 in the Ashkenazi Jewish population. The results of a NIH Consensus Development Conference on Genetic Testing for Cystic Fibrosis were published in 1999. The expert panel of 14 members representing multiple medical specialties formally recommended DNA testing for CF for the following individuals:

adults with a positive family history of cystic fibrosis
partners of people with CF
couples planning a pregnancy and couples presenting for prenatal care
males with congenital bilateral absence of the vas deferens

DNA testing for cystic fibrosis at the Greenwood Genetic Center screens for the 33 most common mutations, to detect approximately 90% of mutations causing CF occurring in Caucasians. 97% of Ashkenazi Jewish CF mutations will be detected by this analysis.

Specimen Requirements: 5 to 10 ml of peripheral blood in an EDTA (lavender top) Vacutainer tube. The minimal amount needed for reliable DNA isolation is 3 ml. If necessary, ACD Solution A Vacutainer tubes (yellow top) may be substituted. Prenatal testing is available from amniocytes and CVS material.

Transport: Please contact the Molecular Diagnostic Laboratory Coordinator (1-800-473-9411) for shipping information. The specimen should be kept at room temperature and delivered via overnight shipping. FedEx delivery is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on a Friday can be safely designated for Monday delivery.

Analysis Standards: Analysis will be completed within 1 week of sample receipt. The quality and interpretation of test results are assessed by the laboratory director. Technical staff independently assess the quality and interpretation of the test. The Greenwood Genetic Center Molecular Diagnostic Laboratory is CLIA certified and actively participates in CAP proficiency surveys.

Reporting of Test Results: Test results and interpretation will be mailed and/or faxed following completion of the test. Reports will be telephoned to the person(s) requesting the test when an abnormal test result occurs.

CPT Codes: 83909, 83914 (x10), 83912