Complete Blood Count (CBC) Test: What Patients Need to Know

A complete blood count, or CBC, is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It gives your healthcare provider a broad picture of your overall health and can help detect a wide range of conditions, from infections and anemia to blood disorders.

The ACVRL1 gene targeted mutation analysis is a specialized genetic test that looks for specific changes (mutations) in the ACVRL1 gene. This gene provides instructions for making a protein that helps regulate blood vessel formation and function. When mutations occur in this gene, they can cause hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome.

The test is performed with a simple blood draw, usually from a vein in your arm. A healthcare professional will clean the site, wrap a band around your upper arm, and collect a small sample into a tube. The entire process takes only a few minutes, and you may feel a brief pinch. You can typically return to your normal activities right away.

A healthcare provider will collect a blood sample from a vein in your arm. The sample is then sent to a laboratory where molecular genetics techniques are used to extract and analyze your DNA. The laboratory specifically looks for known disease-causing mutations in the ACVRL1 gene. The test does not examine your entire genetic makeup—just the specific gene associated with HHT.

Your doctor may order a CBC as part of a routine health checkup, or to help diagnose symptoms such as fatigue, weakness, fever, bruising, or unexplained weight loss. It is also used to monitor existing conditions, track how well a treatment is working, or check your blood before or during certain medications and procedures.

This test is typically ordered when: you have symptoms suggesting HHT (such as nosebleeds, telangiectasias, or arteriovenous malformations); you have a family history of HHT; or a family member has already been diagnosed with an ACVRL1 mutation. The test helps confirm whether symptoms are due to HHT and identifies family members who may be at risk.

Results show whether your blood cell counts fall within the normal reference ranges. High white blood cell counts may suggest an infection or inflammation, while low red blood cell counts can indicate anemia. Abnormal platelet levels may affect clotting. Your provider will interpret your results together with your symptoms, medical history, and other tests to determine what they mean for you and whether further evaluation is needed.

A positive result means a pathogenic (disease-causing) mutation was found in the ACVRL1 gene. This confirms a diagnosis of HHT and means you can pass the mutation to your children (each child has a 50% chance of inheriting it). A negative result means no known pathogenic mutation was found. However, this does not completely rule out HHT, as there may be mutations in other genes (like ENG) or rare mutations not detected by this test. A variant of uncertain significance means a genetic change was found but its health impact is unknown.