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Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene; over 1,600 different CFTR mutations have been reported. CF is associated with recurrent pulmonary infections and pancreatic dysfunction.
Tests generally appear in the order most useful for common clinical situations
| Test name: Cystic Fibrosis (CFTR) 32 Mutations |
| ARUP #: 2001933 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation/Fragment Analysis |
| Use: Tests for 32 common CFTR gene mutations Order for any of the following indications
Clinical sensitivity varies with ethnicity |
| Limitations: Mutations other than the 32 tested will not be detected Primer site mutations may affect this assay |
| Test name: Cystic Fibrosis (CFTR) 32 Mutations with Reflex to Sequencing |
| ARUP #: 2001968 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation/Fragment Analysis/Sequencing |
| Use: Tests for 32 common CFTR gene mutations; if two CFTR mutations are not identified sequencing is performed Sequencing detects 97% of the described CF mutations (currently >1,600) Order for patients with either of the following indications (if not previously tested using the CF mutation panel)
If only one pathogenic mutation is identified, CFTR gene sequencing will be added Clinical sensitivity: 97% in all ethnicities |
| Limitations: CFTR promoter mutations, deep intronic mutations and large gene deletions/duplications will not be detected |
| Test name: Cystic Fibrosis (CFTR) 32 Mutations with Reflex to Sequencing and Reflex to Deletion/Duplication |
| ARUP #: 2001967 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation/Fragment Analysis/Sequencing/Multiplex Ligation-dependent Probe Amplification |
| Use: Tests for 32 common CFTR gene mutations Sequencing is performed if only 1 mutation is identified; deletion/duplication testing is performed if two CFTR mutations are not identified by sequencing Clinical sensitivity is 99% Cost-effective method for determining causative mutations in patients with a clinical diagnosis of CF |
| Limitations: CFTR promoter mutations and deep intronic mutations will not be detected |
| Test name: Cystic Fibrosis (CFTR) 32 Mutations, Fetal |
| ARUP #: 2001970 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation/Fragment Analysis |
| Use: Test amniocyte for 32 common CF gene mutations Order in fetal samples for the following indications
Clinical sensitivity varies with ethnicity |
| Limitations: Only the 32 mutations tested will be detected; further mutations within the primer/probe regions could affect this assay |
| Test name: Cystic Fibrosis (CFTR) Deletion/Duplication |
| ARUP #: 0051642 |
| Methodology: Multiplex Ligation Probe Amplification |
| Use: Detects large CFTR duplications and deletions within the exons and intron/exon borders Order for patients who have a positive sweat chloride test or atypical CF symptoms but have only one or no detectable mutations on CFTR sequencing ~1-2% of CFTR mutations are large deletions or duplications |
| Limitations: Deletion/duplication breakpoints will not be determined CFTR single-base pair substitutions, small deletions/duplications, and deep intronic and promoter mutations will not be detected Mutations within the primer/probe regions could affect this assay |
| Test name: Cystic Fibrosis (CFTR) Sequencing |
| ARUP #: 0051110 |
| Methodology: Polymerase Chain Reaction/Scanning/Sequencing |
| Use: Detects 97% of described CFTR gene mutations (currently >1,600) Order for patients with symptoms of classic or atypical CF but without two mutations identified by the CF mutation panel |
| Limitations: Rare diagnostic errors can occur due to primer site mutations Regulatory region mutations, large gene deletions/duplications and some deep intronic mutations will not be detected |
| Test name: Cystic Fibrosis (CFTR) Sequencing with Reflex to Deletion/Duplication |
| ARUP #: 0051640 |
| Methodology: Polymerase Chain Reaction/Sequencing/Multiplex Ligation Probe Amplification |
| Use: Tests for nearly all described CFTR gene mutations (currently >1,600) If sequencing identifies fewer than 2 pathogenic mutations, CFTR deletion/duplication will be added Order for patients with symptoms of classic or atypical CF but without two mutations identified using the CF mutation panel Clinical sensitivity: 99% |
| 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 |
| Test name: Cystic Fibrosis Cis-Trans (CFTR) R117H & 5T Mutations |
| ARUP #: 0056006 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation |
| Use: Determines if the R117H mutation and 5T variant are on the same chromosome Order only for patients who have a previously identified R117H mutation and 5T variant |
| Test name: Cystic Fibrosis (CFTR) 32 Mutations, Atypical |
| ARUP #: 2001969 |
| Methodology: Polymerase Chain Reaction/Oligonucleotide Ligation/Fragment Analysis |
| Use: Tests for 32 common CFTR gene mutations, including 5T Order for patients with one or more of the following symptoms
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| Limitations: Mutations other than the 32 tested will not be detected Primer site mutations may affect analytic sensitivity |
| Test name: Cystic Fibrosis (CFTR) 3199del6 Mutation |
| ARUP #: 0050098 |
| Methodology: Polymerase Chain Reaction/Fluorescence Monitoring |
| Use: Tests for 3199del6 mutation only Order only for patients who have a previously identified I148T mutation |
| Limitations: Other mutations in the CFTR gene will not be detected |
| Test name: Pancreatic Elastase, Fecal |
| ARUP #: 0080526 |
| Methodology: Quantitative Enzyme-Linked Immunosorbent Assay |
| Use: Screen for pancreatic insufficiency caused by CF |
| Limitations: Watery stool samples may produce falsely decreased results due to a dilution effect |
| Test name: Cystic Fibrosis (CFTR) 5T Mutation |
| ARUP #: 0056003 |
| Methodology: Polymerase Chain Reaction/Fragment Analysis |
| Comments: Approval by an ARUP genetic counselor required prior to ordering |
| Test name: Cystic Respiratory Culture |
| ARUP #: 0060130 |
| Methodology: Standard reference procedure for aerobic bacterial culture and identification |
| Comments: |