For individuals with suspected CF but without 2 pathogenic variants detected by the CF 165 pathogenic variants test.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Patient History Form is available on the ARUP Web site or by contacting ARUP Client Services at (800) 522-2787.
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
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 bronchiectasis in non-classic cystic fibrosis (CF).
Incidence of Classic CF: 1 in 3,000 Caucasians or Ashkenazi Jewish, 1 in 8,000 Hispanics, 1 in 15,000 African Americans, 1 in 32,000 Asians.
Incidence of Nonclassic CF: Unknown.
Inheritance: Autosomal recessive.
Penetrance: High for severe mutations, variable for mild/moderate mutations.
Cause of Classic CF: Two deleterious CFTR mutations on opposite chromosomes.
Cause of Nonclassic CF: Typically one severe and one mild/moderate CFTR mutations on opposite chromosomes.
Mutations Tested: Base pair substitutions and deletions/duplications within the coding region and intron-exon boundaries; additionally, two deep intronic mutations (3849+10kbC>T and 1811+1.6kbA>G).
Clinical Sensitivity: 99 percent.
Methodology for Sequencing: Bidirectional sequencing of the entire CFTR coding region, intron-exon boundaries and two deep intronic mutations.
Methodology for Deletion/Duplication: Multiplex ligation-dependent probe amplification (MLPA) to detect large CFTR coding region deletions /duplications.
Analytical Sensitivity & Specificity for Sequencing: 99 percent.
Analytical Sensitivity & Specificity for MLPA: 98 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Breakpoints for large deletions/duplications will not be determined. Regulatory region and some deep intronic mutations will not be detected.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0051639||Cystic Fibrosis Seq, w/Rflx DelDup Int|
|2001346||Cystic Fibrosis Seq, w/Rflx DelDup Spec|
- CFTR sequencing reflex