Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Mutation Analysis by Whole Blood DNA Testing
This test checks for specific genetic mutations linked to cystic fibrosis (CF) by examining DNA from your blood. It helps determine if you carry the genes responsible for CF or related conditions.
["Identifies potential cystic fibrosis risk through genetic testing from blood samples."]
Key facts at a glance
- LOINC
- 98038-3
- Short code
- CFTRFMR1SMN1
- Synonyms
- CFTR+FMR1+SMN1 Mut Anl Bld/T
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) blood collection tube for whole blood; sterile container for tissue specimens. DNA extraction requires appropriate storage conditions.
- Units
- N/A
- Ref low
- 5
- Ref high
- 44
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81220
- SNOMED
- 426396006
- Specimen volume
- Whole blood: 3-5 mL (minimum 1 mL for pediatric samples); Tissue: 5-10 mg in sterile saline or transport medium. Prenatal samples: 10-15 mL amniotic fluid or 5-10 mg chorionic villus sample.
- Stability
- Whole blood stable at room temperature (18-25°C) for 48-72 hours; refrigerated (2-8°C) for up to 7 days; frozen (-20°C or lower) for long-term storage. DNA extracted from blood is stable at 2-8°C for several months or at -20°C for years. Tissue samples should be frozen at -80°C or processed immediately.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
Your healthcare provider may order this test to help diagnose a medical condition, monitor an ongoing health problem, or screen for disease before symptoms appear. It can also be used to check how well a current treatment is working or to investigate abnormal findings from earlier tests and exams.
Your healthcare provider may recommend this test if you have symptoms of CF (such as chronic lung infections, digestive issues, or salt loss), a family history of CF, or if you’re considering pregnancy and have a partner with a known CF mutation. It’s also used for newborn screening in some regions.
This test works by analyzing a sample collected from your body, such as blood, urine, or tissue, in a certified laboratory. Specialized equipment and trained professionals examine the sample for specific markers, and the findings are compared against established reference ranges to produce your result.
A small blood sample is taken to collect DNA. Specialized lab techniques analyze this DNA to identify known CFTR mutations. The test looks for variations in the gene that codes for the CFTR protein, which regulates salt and water balance in cells.
Before the test, your provider will give you specific instructions, which may include fasting for a set number of hours, avoiding certain medications or supplements, or drinking plenty of water. Tell your care team about all medicines you take and any allergies you have, and plan to arrive on time so your sample can be collected properly.
No special preparation is needed. You may have a simple blood draw, similar to a routine blood test. If you’re undergoing this test for pregnancy planning, discuss any concerns with your provider beforehand.
Your results are usually reported as normal, abnormal, or borderline, depending on how they compare with the reference range for people of your age and sex. A normal result generally suggests no evidence of the condition being tested for, while an abnormal result does not always mean you are ill. Your provider will review the findings alongside your symptoms, medical history, and other tests before making a diagnosis or recommending next steps.
Results can indicate whether you carry one or both copies of a CFTR mutation. If you have two mutations, it strongly suggests a higher risk of CF. If only one mutation is found, it may indicate a carrier status, depending on the mutation’s severity.
Reference range
CFTR: No pathogenic mutations detected in analyzed regions (common mutations including ΔF508, G551D, N1303K, R117H, W1282X, and others). FMR1 (CGG repeat): Normal: 5-44 repeats; Intermediate (gray zone): 45-54 repeats; Premutation: 55-200 repeats (males and females); Full mutation: >200 repeats. SMN1: Two copies of SMN1 detected (normal); homozygous deletion of SMN1 exon 7 indicates SMA carrier status or affected status depending on copy number of SMN2. Results should be interpreted in conjunction with clinical findings and family history.N/A
No special fasting or dietary restrictions required. Patient should provide informed consent for genetic testing. A detailed family history and clinical indication for testing should be documented. Genetic counseling is recommended before and after testing. For prenatal testing or testing of minors, appropriate consent and ethical guidelines must be followed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
CFTR Mutation Screening
Frequently asked questions
This test is critical for diagnosing CF early, especially in newborns or those with suspected symptoms. It also guides family planning decisions, as CF is hereditary. Knowing your mutation status can help manage symptoms and access specialized care.
A positive result means you carry one or more mutations linked to CF. If you have two such mutations, you may have CF or be at higher risk. If only one mutation is found, you’re a carrier and may pass it to your children. Always discuss results with your healthcare provider for personalized guidance.
This test is typically done once, unless you have specific symptoms, a family history, or are undergoing genetic counseling. Follow-up testing may be recommended if you’re pregnant or planning a family.
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