Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Protein Measurement
This test measures the amount of CFTR protein in your blood, which helps assess how well your cystic fibrosis (CF) lungs and digestive system are functioning.
["CFTR protein levels can indicate the severity of cystic fibrosis symptoms and guide treatment decisions."]
Key facts at a glance
- LOINC
- 38448-7
- Short code
- CFTR455
- Synonyms
- CFTR p.A455E Bld/T Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA lavender-top tube (for whole blood) or sterile container (for tissue specimen)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- molgen
- CPT
- 81223
- SNOMED
- 53034004
- Specimen volume
- 3-5 mL whole blood collected in EDTA tube; 5-10 mg tissue in sterile container
- Stability
- Whole blood: 7 days at 2-8°C; long-term storage at -20°C or -80°C. Tissue: 24-48 hours at 2-8°C; long-term storage at -80°C. DNA extracted from specimen is stable for several years at -20°C.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–504 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may order this test if you have cystic fibrosis or are at risk for it. It helps monitor how well your body produces CFTR protein, which is crucial for managing symptoms like lung infections, poor growth, and digestive issues.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw a blood sample. This is usually quick and painless, though you might feel a slight pinch.
What the Results Mean
Lower than expected CFTR protein levels may suggest poor CFTR function, which can affect lung health and digestion. Higher levels might indicate better function, but results vary by individual. Your doctor will discuss these findings with you.
Common Reasons for Testing
This test is often used to evaluate CFTR function in newborns, children, or adults with suspected or diagnosed cystic fibrosis to tailor treatments like pancreatic enzymes, antibiotics, or physical therapy.
Reference range
Negative for CFTR p.Ala455Glu mutation. The wild-type allele is detected in the absence of the variant. Heterozygous or homozygous presence of the variant is reported qualitatively as Detected or Not Detected.N/A
No special patient preparation is required. Patients should provide informed consent for genetic testing. Genetic counseling is recommended before and after testing. A detailed family history of cystic fibrosis or related disorders is helpful for interpretation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CFTR Protein Level
Frequently asked questions
What does a low CFTR protein level mean?
How often should I get this test?
Can diet affect CFTR protein levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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