Complete Blood Count (CBC) Test
This genetic test detects large deletions or duplications in the ACVRL1 and ENG genes, which are associated with Hereditary Hemorrhagic Telangiectasia (HHT).
{"The test uses MLPA technology to find large genetic changes (deletions/duplications) in two specific genes","It helps diagnose Hereditary Hemorrhagic Telangiectasia (HHT), a condition causing abnormal blood vessels","A blood or tissue sample is required for testing","Results can guide treatment and family screening decisions"}
Key facts at a glance
- LOINC
- 69481-0
- Short code
- ACVRL1/ENG MLPA
- Synonyms
- ACVRL1+ENG gene Del+Dup Bld/T MLPA
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA tube (purple top) or ACD tube (yellow top)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- MLPA (Multiplex Ligation-dependent Probe Amplification)
- CPT
- 81403
- SNOMED
- 429060002
- Specimen volume
- 3-5 mL whole blood
- Stability
- Whole blood: room temperature 24-72 hours, refrigerated 72 hours to 7 days. Extracted DNA: refrigerated 1 week, frozen -20°C indefinitely
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–336 hours
- Order
- routine
What is a complete blood count (CBC) test and what does it measure in my blood?
This test looks for large deletions (missing pieces) or duplications (extra copies) in two genes called ACVRL1 and ENG. These genes are important for normal blood vessel development. The test uses a technique called MLPA (Multiplex Ligation-dependent Probe Amplification), which can detect these larger genetic changes that standard genetic sequencing might miss.
Why might my healthcare provider order a complete blood count (CBC) test for me?
Your doctor may recommend this test if you or your family members have symptoms of Hereditary Hemorrhagic Telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome. Common signs include frequent nosebleeds, red spots on the skin and mucous membranes (telangiectasias), and arteriovenous malformations (AVMs) in the lungs, brain, or liver. This test can confirm a genetic diagnosis and help identify family members who may be at risk.
How is a complete blood count (CBC) test performed, and what should I expect during the blood draw?
A healthcare professional will collect a blood sample from a vein in your arm, or in some cases, a tissue sample may be used. The sample is then sent to a specialized laboratory where MLPA technology is used to analyze the ACVRL1 and ENG genes for deletions or duplications. The procedure is simple and takes only a few minutes to collect the sample.
What do my complete blood count (CBC) results mean, and how will I receive them?
A 'positive' result means a deletion or duplication was found in the ACVRL1 or ENG gene, which supports a diagnosis of HHT. A 'negative' result means no large deletion or duplication was found, but it does not completely rule out HHT because other types of genetic changes (smaller mutations) may still be present. Your doctor will interpret the results in the context of your symptoms and family history.
Reference range
No deletion or duplication detected in ACVRL1 and ENG genes. Pathogenic variants not identified.N/A
No special preparation required. Patient may eat and drink normally before specimen collection. Inform patient that this is a genetic test with implications for family members.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used to confirm a diagnosis of Hereditary Hemorrhagic Telangiectasia (HHT), a genetic disorder causing abnormal blood vessel formation. Identifying the specific genetic cause helps guide clinical management, including screening for potentially serious complications like lung and brain AVMs. Family members can also be tested to determine if they carry the same genetic change, enabling early monitoring and intervention if needed.
Frequently asked questions
How long does it take to get results?
Do I need to fast before this test?
Will my insurance cover this test?
Can this test detect all types of genetic mutations?
Should my family members also be tested?
Sources
- 1
- 2
- 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