Ordering Recommendation

For individuals with suspected CF but without 2 pathogenic variants detected by the CF 165 pathogenic variants test. This test is NOT indicated for routine obstetric carrier screening.

Mnemonic

CFTR FGA

Methodology

Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification

Performed

Varies

Reported

28-35 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
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.

Unacceptable Conditions
Remarks

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

Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

Test Number
Components
Reference Interval
0051110 Cystic Fibrosis (CFTR) Sequencing (Temporary Referral as of 12/07/20) By report
0051642 Cystic Fibrosis (CFTR) Deletion/Duplication (INACTIVE as of 02/16/21: Refer to 3003144 in the February Hotline)

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 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.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)

Note

 If sequencing identifies less than two pathogenic mutations, then CFTR deletion/duplication will be added. Additional charges apply.

Hotline History

N/A

CPT Codes

81223; if reflexed, add 81222

Components

Component Test Code* Component Chart Name LOINC
0051639 Cystic Fibrosis Seq, w/Rflx DelDup Int
2001346 Cystic Fibrosis Seq, w/Rflx DelDup Spec
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • CFTR sequencing reflex
Cystic Fibrosis (CFTR) Sequencing with Reflex to Deletion/Duplication (Temporary Referral as of 12/07/20)