| Cystic Fibrosis 23 Mutations (CFTR 23) | |
|---|---|
| Test Mnemonic: | CFTR 23 |
| Specimen Requirements: | Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution). For other sample types, for example, saliva and extracted genomic DNA, please consult molecular diagnostics lab (phone 409-772-4197) |
| Test Included: | To identify couples at risk of having a child with classic CF following the American College of Obstetricians and Gynecologists and the American College of Medical Genetics and Genomic current guidelines for prenatal and preconception carrier screening for CF. |
| Minimum Volume: | 1 ml whole blood |
| Storage/Transport: | Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month |
| Specimen Preparation: | No processing is required |
| Causes for Rejection: | Incomplete and/or incorrect sample identification, hemolyzed samples |
| Reference Range: | Negative |
| Turnaround Time: | 3-7 days |
| Methodology: | GenMark Cystic Fibrosis Genotyping Test |
| Performed: | Molecular Diagnostics Laboratory |
| Synonyms: | classic cystic fibrosis, CF DNA analysis, CFTR, CF carrier screen, CF molecular testing, CF genotyping |
| Clinical Indication: | CF carrier screening for expectant individuals and those planning a pregnancy |
| Patient Preparation : | No processing is required |
| CPT 4 Code: | 81220 and 81224 |
| Note: | BACKGROUND INFORMATION PHENOTYPE CHARACTERISTICS: Chronic sino-pulmonary disease, gastrointestinal malabsorption/pancreatic insufficiency, and obstructive azoospermia. Findings are often limited to a single organ system such as isolated pancreatitis, bilateral absence of the vas deferens, nasal polyposis, or broncheictasis in non-classic CF. INCIDENCE: 1 in 3,000 Caucasians or Ashkenazi Jewish, 1 in 8,000 Hispanics, 1 in 15,000 African Americans, 1 in 32,000 Asians. INHERITANCE: Autosomal recessive. PENETRANCE: High for severe mutations, variable for mild mutations. CAUSE: Two CFTR mutations on opposite chromosomes. MUTATIONS TESTED: G85E (c.254G>A), R117H (c.350G>A), R334W (c.1000C>T), R347P (c.1040G>C), A455E (c.1364C>A), I507del (c.1519_1521delATC), F508del (c.1521_1523delCTT), G542X (c.1624G>T), G551D (c.1652G>A), R553X (c.1657C>T), R560T (c.1679G>C), 621+1G>T (c.489+1G>T), 711+1G>T (c.579+1G>T), R1162X (c.3484C>T), W1282X (c.3846G>A), N1303K (c.3909C>G), 1717-1G>A (c.1585-1G>A), 1898+1G>A (c.1766+1G>A), 2184delA (c.2052delA), 2789+5G>A (c.2657+5G>A), 3120+1G>A (c.2988+1G>A), 3659delC (c.3528delC), 3849+10kbC>T (c.3717+12191C>T), and IVS-8/poly T (c.1210-12T[5_9]. The mutations tested are listed above according to the legacy nomenclature; the standard nomenclature is listed in parentheses. Panel mutations are reported according to the legacy nomenclature. CLINICAL SENSITIVITY: Ashkenazi Jewish 94 percent; Caucasian 88 percent; Hispanic 72 percent; African American 65 percent; Asian American 49 percent. METHODOLOGY: Mutation is detected using genomic DNA, multiplex polymerase chain reaction, and eSensor XT-8 System. Assay uses U.S. Food and Drug Administration (FDA) approved kit (GenMark Diagnostics). ANALYTICAL SENSITIVITY AND SPECIFICITY: 99 percent. LIMITATIONS: Rare diagnostic errors can occur due to primer or probe site mutations. Only the 23 CFTR mutations listed above will be interrogated. Counseling and informed consent are recommended for genetic testing.
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| When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent. | |