Test ID: CFTRM
CFTR Gene, Full Gene Analysis
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Follow-up testing to identify mutations in individuals with a clinical diagnosis of cystic fibrosis (CF) and a negative targeted mutation analysis for the common mutations
Identification of mutations in individuals with atypical presentations of CF (eg, congenital bilateral absence of the vas deferens or pancreatitis)
Identification of mutations in individuals where detection rates by targeted mutation analysis are low or unknown for their ethnic background
Identification of patients who may respond to CFTR potentiator therapy
This is not the preferred genetic test for carrier screening or initial diagnosis. For these situations, order CFPB/9497 Cystic Fibrosis Mutation Analysis, 106-Mutation Panel
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Not the preferred first-tier molecular test for carrier screening or diagnosis. Used to identify mutations in individuals with a clinical diagnosis of cystic fibrosis (CF) when CFPB/9497 Cystic Fibrosis Mutation Analysis, 106-Mutation Panel is negative or uninformative.
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
See Cystic Fibrosis Molecular Diagnostic Testing Algorithm in Special Instructions for additional information.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Polymerase Chain Reaction (PCR)/DNA Sequencing/Dosage Analysis (Multiplex Ligation-Dependent Probe Amplification [MLPA])
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Congenital Bilateral Absence of the Vas deferens (CBAVD)
Cystic Fibrosis Transmembrane Conductance
Pancreatitis
Cystic Fibrosis (CF)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen must arrive within 96 hours of draw.
Container/Tube: Lavender top (EDTA) or yellow top (ACD)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube.
Additional Information: Patient education brochures in English (Supply T548) and Spanish (Supply T563) are available upon request.
Forms:
1. Molecular Genetics-Congenital Inherited Diseases Patient Information Sheet (Supply T521) in Special Instructions
2. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
3. If not ordering electronically, submit a Molecular Genetics Request Form (Supply T245) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
No specimen should be rejected.
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Frozen | ||
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Cystic fibrosis (CF), in the classic form, is a severe autosomal recessive disorder characterized by a varied degree of chronic obstructive lung disease and pancreatic enzyme insufficiency. Clinical diagnosis is generally made based on these features, combined with a positive sweat chloride test or positive nasal potential difference. CF can also have an atypical presentation and may manifest as congenital bilateral absence of the vas deferens (CBAVD), chronic idiopathic pancreatitis, bronchiectasis, or chronic rhinosinusitis. 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.
If a clinical diagnosis of CF has been made, molecular testing for common CF mutations is available. To date, over 1,500 mutations have been described within the CF gene, named cystic fibrosis transmembrane conductance regulator (CFTR). The most common mutation, deltaF508, accounts for approximately 67% of the mutations worldwide and approximately 70% to 75% in the North American Caucasian population. Most of the remaining mutations are rather rare, although some show a relatively higher prevalence in certain ethnic groups or in some atypical presentations of CF, such as isolated CBAVD.
The recommended approach for confirming a CF diagnosis or detecting carrier status begins with molecular tests for the common CF mutations (eg, CFPB/9497 Cystic Fibrosis Mutation Analysis, 106-Mutation Panel). This test, CFTR Gene, Full Gene Analysis may be ordered if 1 or both disease-causing mutations are not detected by the targeted mutation analysis (CFPB/9497). Full gene analysis, sequencing and dosage analysis of the CFTR gene, is utilized to detect private mutations. Together, full gene analysis of the CFTR gene and deletion/duplication analysis 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 1 copy of the G551D mutation.
See Cystic Fibrosis Molecular Diagnostic Testing Algorithm in Special Instructions for additional information.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
Interpretation Provides information to assist in interpretation of the test results
An interpretive report will be provided.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A small percentage of individuals who have a diagnosis of cystic fibrosis (CF) may have a mutation that is not identified by this method (eg, promoter mutations, deep intronic alterations). The absence of a mutation(s), therefore, does not eliminate the possibility of positive carrier status or the diagnosis of CF. For carrier testing, it is important to first document the presence of a cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation in an affected family member.
In some cases, DNA alterations of undetermined significance may be identified.
Rare polymorphisms exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical findings, additional testing should be considered.
A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant.
Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.
In addition to disease-related probes, the multiplex ligation-dependent probe amplification technique utilizes probes localized to other chromosomal regions as internal controls. In certain circumstances, these control probes may detect other diseases or conditions for which this test was not specifically intended. Results of the control probes are not normally reported. However, in cases where clinically relevant information is identified, the ordering physician will be informed of the result and provided with recommendations for any appropriate follow-up testing.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Rosenstein BJ, Zeitlin PL: Cystic fibrosis. Lancet 1998 Jan 24;351(9098):277-282
2. Strom CM, Huang D, Chen C, et al: Extensive sequencing of the cystic fibrosis transmembrane regulator gene: assay validation and unexpected benefits of developing a comprehensive test. Genet Med 2003 Jan-Feb;5(1):9-14
3. Ramsey BW, Davies J, McElvaney NG, et al: A CFTR Potentiator in Patients with Cystic Fibrosis and the G551D Mutation. NEJM 2011 Nov 3:365(18):1663-1672
Method Description Describes how the test is performed and provides a method-specific reference
DNA sequencing is used to test for the presence of a mutation in all 27 exons of the CFTR gene. Additionally, gene dosage analysis by multiplex ligation-dependent probe amplification is used to test for the presence of large deletions and duplications in this gene.(Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Wednesday; 10 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
81223-CFTR (cystic fibrosis transmembrane conductance regulator) (eg, cystic fibrosis) gene analysis; full gene sequence
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 27242 | Specimen | 31208-2 |
| 27243 | Specimen ID | N/A |
| 27244 | Source | N/A |
| 27245 | Order Date | N/A |
| 27246 | Reason For Referral | 42349-1 |
| 27247 | Method | In Process |
| 27248 | Result | 21654-9 |
| 27249 | Interpretation | 69047-9 |
| 51011 | Extraction Performed? | N/A |
| 51012 | MLPA Performed? | N/A |
| 27250 | Amendment | In Process |
| 27251 | Reviewed By: | N/A |
| 27252 | Release Date | N/A |
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