ARUP's Laboratory Test Directory

Cystic Fibrosis (CFTR) Sequencing with Reflex to Deletion/Duplication : 0051640
[ image for: Patient History For Cystic Fibrosis (CF) Testing]
Patient History For Cystic Fibrosis (CF) Testing
  


Mnemonic: CFTR FGA

Ordering Recommendation: Diagnostic testing for cystic fibrosis.
Methodology: Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification
Performed: Varies
Reported: Within 35 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 2 mL)

Storage/Transport Temperature: Refrigerated.

Remarks: Patient History Form is available on the ARUP Web site or by contacting ARUP Client Services at (800) 522-2787.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Reference Interval:
Test Number Components Reference Interval
0051110Cystic Fibrosis (CFTR) Sequencing By report
0051642Cystic Fibrosis (CFTR) Deletion/Duplication

Interpretive Data: Background information for Cystic Fibrosis (CFTR) Sequencing with Reflex to Deletion/Duplication:
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 Detected: 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: Rare diagnostic errors can occur due to primer and probe site mutations. 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 at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
Note:  If sequencing identifies less than two pathogenic mutations, then CFTR deletion/duplication will be added. Additional charges apply.
CPT Code(s): 81223.  If reflex, add 81222