ADA deficiency, or Adenosine Deaminase Deficiency, is a rare genetic disorder that affects the immune system. Testing for ADA deficiency usually involves a combination of blood tests and genetic analysis. Here's a breakdown of the typical testing process:
Blood Tests
- Complete Blood Count (CBC): This test measures the number of different types of blood cells, including white blood cells, which are crucial for fighting infections. In individuals with ADA deficiency, the white blood cell count, especially lymphocytes, is often low.
- Lymphocyte Subset Analysis: This test further examines the different types of lymphocytes, specifically T cells and B cells, which play distinct roles in the immune response. ADA deficiency often leads to a significant decrease in T cell counts.
- Adenosine Deaminase (ADA) Enzyme Activity: This test directly measures the activity of the ADA enzyme in red blood cells. A low ADA enzyme activity confirms the diagnosis of ADA deficiency.
Genetic Analysis
- DNA Sequencing: This test analyzes the gene responsible for producing the ADA enzyme. It identifies any mutations or variations in the gene that might cause ADA deficiency.
Other Tests
- Immunoglobulin Levels: This test measures the levels of antibodies in the blood. Individuals with ADA deficiency may have low levels of immunoglobulins, reflecting a compromised immune system.
Diagnosis
A combination of these tests helps doctors diagnose ADA deficiency. A low ADA enzyme activity and genetic confirmation are usually considered definitive for diagnosis.
