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Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Protein Variant Analysis by Next-Generation Sequencing (NGS)

Published: August 9, 2026Updated: August 16, 2026

This test checks for genetic variations in the CFTR gene, which may be linked to cystic fibrosis or other related conditions.

Quick summary

["Helps identify potential genetic causes of respiratory or digestive issues."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
34729-4
Short code
CFTR117H5T
Synonyms
CFTR p.R117h+5T Var Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
EDTA (lavender/purple-top) blood collection tube for whole blood samples. Tissue samples should be collected in sterile containers with appropriate transport medium. Commercial DNA extraction from buccal swabs or saliva is also acceptable when validated.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
molgen
CPT
81220
SNOMED
5304006
Specimen volume
3-5 mL whole blood in EDTA tube; minimum 1 mL for pediatric samples. Tissue: minimum 25-50 mg in sterile container. Extracted DNA: minimum 50-100 ng/μL with A260/A280 ratio of 1.8-2.0.
Stability
Whole blood: Stable at room temperature (18-25°C) for 48-72 hours; refrigerated (2-8°C) for up to 1 week. Extracted DNA: Stable at 2-8°C for 1 month; at -20°C for long-term storage (1+ years). Avoid repeated freeze-thaw cycles. Tissue samples should be processed or frozen at -80°C within 24 hours.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
72–336 hours
Order
routine

What This Test Measures

The test analyzes DNA from a blood sample to detect specific changes (mutations) in the CFTR gene. These mutations can affect how the CFTR protein functions, which is important for managing conditions like cystic fibrosis.

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of cystic fibrosis (such as chronic lung infections, digestive problems, or unexplained weight loss) or if you have a family history of cystic fibrosis.

Sample Collection and Preparation

A small blood sample is drawn from your arm. The blood is then processed to extract DNA for testing. This process is usually quick and done in a clinical setting.

What to Expect Before the Test

No special preparation is typically needed, but you may be asked to avoid certain medications that could interfere with results. If you are pregnant or have a known allergy to blood tests, let your provider know.

Reference range

Negative for CFTR p.Arg117His (R117H) mutation and Negative for 5T variant (Normal: 7T or 9T poly-T tract). Reportable results include: p.Arg117His Not Detected / 5T Not Detected; p.Arg117His Not Detected / 5T Detected; p.Arg117His Detected (Heterozygous or Homozygous) / 5T Not Detected; p.Arg117His Detected (Heterozygous or Homozygous) / 5T DetectedN/A

Specimen: whole-blood

No special preparation or fasting required. Patients should be informed about the genetic nature of the test and provide informed consent. Pre-test genetic counseling is recommended, especially for individuals with family history of cystic fibrosis or those considering reproductive planning. Patients should provide relevant clinical and family history information.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Identifying CFTR gene mutations can confirm a diagnosis of cystic fibrosis or other genetic disorders affecting chloride transport. Early detection allows for tailored treatment plans, including enzyme replacements, physical therapy, and monitoring to manage symptoms.

Short name

CFTR Gene Mutation Screening

Frequently asked questions

What does a positive result mean?
A positive result indicates the presence of known or suspected CFTR gene mutations that may contribute to cystic fibrosis or related conditions. This finding helps guide further medical evaluation and treatment options.
How long will it take to get results?
Results are usually available within 2 to 4 weeks, depending on the laboratory and testing complexity. Your healthcare provider will discuss the results with you in detail.
Are there any risks or side effects from this test?
The most common side effect is a minor bruise or soreness at the needle insertion site. Rarely, there may be a reaction to the blood draw, such as fainting or swelling. Most side effects are mild and resolve quickly.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy