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Test Code CFTRN Cystic Fibrosis Transmembrane Conductance Regulator, CFTR, Full Gene Analysis, Varies


Ordering Guidance


This test is not the preferred test for cystic fibrous carrier screening. See CFMP / Cystic Fibrosis, CFTR Gene, Variant Panel, Varies.

 

Targeted testing for familial variants (also called site-specific or known variants testing) is available for variants identified in the CFTR gene. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about testing option, call 800-533-1710.



Additional Testing Requirements


All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen. This must be a different order number than the prenatal specimen.

 

For cord blood specimens: Maternal cell contamination (MCC) studies are available. Order MATCC on both the cord blood and maternal specimens under separate order numbers. Cord blood testing will proceed without MCC studies, but results may be compromised if MCC is present.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. For instructions for testing patients who have received a bone marrow transplant, call 800-533-1710.

 

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated

 

Specimen Type: Skin biopsy

Supplies: Fibroblast Biopsy Transport Media (T115)

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin.

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.

 

Specimen Type: Cultured fibroblasts

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks

Collection Instructions: Submit confluent cultured fibroblast cells from a skin biopsy from another laboratory.

Specimen Stability Information: Ambient (preferred)/Refrigerated (<24 hours)

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.

 

Due to its complexity, consultation with the laboratory is required for all prenatal testing; call 800-533-1710 to speak to a genetic counselor.

 

Specimen Type: Amniotic fluid

Container/Tube: Amniotic fluid container

Specimen Volume: 20 mL

Specimen Stability Information: Refrigerated (preferred)/Ambient

Additional information:

1. A separate culture charge will be assessed under CULAF / Culture for Genetic Testing, Amniotic Fluid. An additional 2 to 3 weeks is required to culture amniotic fluid before genetic testing can occur.

2. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.

 

Specimen Type: Chorionic villi

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 20 mg

Specimen Stability Information: Refrigerated

Additional Information:

1. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 2 to 3 weeks is required to culture chorionic villi before genetic testing can occur.

2. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.

 

Specimen Type: Confluent cultured cells

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks

Collection Instructions: Submit confluent cultured cells from another laboratory.

Specimen Stability Information: Ambient (preferred)/Refrigerated

Additional Information: All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521)

Secondary ID

619774

Useful For

Follow-up testing to identify variants in individuals with a clinical diagnosis of cystic fibrosis (CF)

 

Identifying genetic variants in individuals with atypical presentations of CF (eg, congenital bilateral absence of the vas deferens or pancreatitis)

 

Identifying genetic variants in individuals where detection rates by targeted variant analysis are low or unknown for their ancestral background

 

Identifying patients who may respond to cystic fibrosis transmembrane conductance regulator (CFTR) potentiator therapy

Genetics Test Information

This test utilizes next-generation sequencing to detect single nucleotide and copy number variants in the CFTR gene associated with cystic fibrosis (CF).

 

Identification of a disease-causing variant may assist with diagnosis, prognosis, clinical management, recurrence risk assessment, familial screening, and genetic counseling for CF.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULFB Fibroblast Culture for Genetic Test Yes No
CULAF Amniotic Fluid Culture/Genetic Test Yes No
MATCC Maternal Cell Contamination, B Yes No

Testing Algorithm

For prenatal specimens only:

-If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture/genetic test will be added at an additional charge.

-If chorionic villus specimen (nonconfluent cultured cells) is received, fibroblast culture for genetic test will be added at an additional charge.

For any prenatal specimen that is received, maternal cell contamination testing will be performed at an additional charge.

 

Skin biopsy or cultured fibroblast specimens:
 If a skin biopsy is received, fibroblast culture testing will be performed at an additional charge. If viable cells are not obtained, the client will be notified.

Method Name

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Reporting Name

CFTR Gene, Full Gene Analysis

Specimen Type

Varies

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Cystic fibrosis (CF), in the classic form, is a severe autosomal recessive disorder characterized by a varying degree of chronic obstructive lung disease and pancreatic enzyme insufficiency.(1) Clinical diagnosis is generally made based on these features, combined with a positive sweat chloride test or positive nasal potential difference.(1) CF can also have an atypical presentation (CFTR-related disorder [CFRD] or CFTR-related metabolic syndrome [CRMS]) and may manifest solely as congenital absence of the vas deferens or chronic idiopathic pancreatitis.(2) Several states have implemented newborn screening for CF, which identifies potentially affected individuals by measuring immunoreactive trypsinogen in a dried blood specimen collected on filter paper.(3)

 

To date, over 2000 variants have been described within the cystic fibrosis transmembrane conductance regulator (CFTR) gene that can cause CF.(3) The most common variant, deltaF508, accounts for approximately 67% of the variants worldwide and approximately 70% to 75% in the North American White population.(4) Most of the remaining variants are rare, although some show a relatively higher prevalence in certain ancestries or in some atypical presentations of CF, such as CFRD or CRMS.

 

If a clinical diagnosis of CF has been made or is suspected, full gene analysis of the CFTR gene may be utilized instead to genetically confirm the diagnosis. Full gene and deletion/duplication analysis of the CFTR gene can identify over 98% of the sequence variants in the coding region and splice junctions.

 

Of note, CFTR potentiator therapies may improve clinical outcomes for patients with a clinical diagnosis of CF and at least one copy of a select subset of variants.(3)

Reference Values

An interpretive report will be provided

Interpretation

All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(5) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Day(s) Performed

Varies

Report Available

28 to 42 days

Specimen Retention Time

Whole blood: 2 weeks (if available); Extracted DNA: 3 months; Cultured fibroblasts, skin biopsy, cord blood, amniotic fluid, cultured amniocytes, chorionic villi, cultured chorionic villi: 1 month

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

81223

88233- Tissue culture, skin, solid tissue biopsy (if appropriate)

88240- Cryopreservation (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CFTRN CFTR Gene, Full Gene Analysis 90256-9

 

Result ID Test Result Name Result LOINC Value
619775 Test Description 62364-5
619776 Specimen 31208-2
619777 Source 31208-2
619778 Result Summary 50397-9
619779 Result 82939-0
619780 Interpretation 69047-9
619781 Additional Results 82939-0
619782 Resources 99622-3
619783 Additional Information 48767-8
619784 Method 85069-3
619785 Genes Analyzed 82939-0
619786 Disclaimer 62364-5
619787 Released By 18771-6