For individuals with suspected CF. This test is NOT indicated for routine obstetric carrier screening. If individual is not symptomatic, order Cystic Fibrosis (CFTR) 165 Pathogenic Variants (2013661).
Polymerase Chain Reaction/Fluorescence Monitoring/Sequencing
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution).
Transport 3 mL whole blood. (Min: 2 mL)
Plasma or serum. Specimens collected in sodium heparin or lithium heparin tubes.
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Background information for Cystic Fibrosis (CFTR), 165 Pathogenic Variants with Reflex to Sequencing:
Characteristics of Classic Cystic Fibrosis (CF): Chronic sino-pulmonary disease, gastrointestinal malabsorption/pancreatic insufficiency, and obstructive azoospermia. Symptoms of a CFTR-related disorder are often limited to a single organ system such as isolated pancreatitis, bilateral absence of the vas deferens, nasal polyposis, or bronchiectasis.
Incidence: 1 in 2,300 Ashkenazi Jewish, 1 in 2,500 Caucasians, 1 in 13,500 Hispanics, 1 in 15,100 African Americans, 1 in 35,100 Asians.
Inheritance: Autosomal recessive.
Penetrance: High for severe pathogenic variants, variable for moderate and mild pathogenic variants.
Cause of Classic CF: Two severe, or one severe and one moderate, pathogenic CFTR variants on opposite chromosomes.
Cause of CFTR-Related Disorders: Two pathogenic CFTR variants on opposite chromosomes in any of the following combinations; two mild, one mild and one severe or one mild and one moderate.
Pathogenic Variants Tested: Refer to Additional Technical Information document.
Clinical Sensitivity of CF 165-Variants Test: Ashkenazi Jewish 96 percent; Caucasian 92 percent; Hispanic 80 percent; African American 78 percent; Asian American 55 percent.
Clinical Sensitivity for Sequencing: 97 percent.
Methodology for 165-Variants Test: Polymerase Chain Reaction (PCR) and fluorescence monitoring.
Methodology for Sequencing: Bidirectional sequencing of the CFTR coding region and intron-exon boundaries.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. CFTR promoter and regulatory region variants and large gene deletions/duplications and inversions will not be detected.
Laboratory Developed Test (LDT)
If less than two pathogenic variants are identified by the CF 165 Variants assay, then CFTR gene sequencing will be performed. Additional charges apply for each tier performed.
81220; if reflexed, add 81223
|Component Test Code*||Component Chart Name||LOINC|
|2013675||Cystic Fibrosis, Allele 1||42938-1|
|2013676||Cystic Fibrosis, Allele 2||42939-9|
|2013681||Cystic Fibrosis, 165 Var. w/Rflx, Interp|
|2013692||Cystic Fibrosis 5T Variant||21654-9|
- CFTR M
- CFTR mutation reflex test