Adenosine Deaminase (ADA) - Serum

Adenosine Deaminase Deficiency (ADA-SCID)

• Disease Type: A rare, autosomal recessive genetic condition that causes Severe Combined Immunodeficiency (SCID) or Chronic Immunodeficiency (CID).
• Cause: Mutations in the ADA gene prevent the breakdown of toxic deoxyadenosine, leading to premature death of lymphocytes.
• Symptoms: Infants with ADA-SCID often show a failure to thrive, persistent diarrhea, extensive dermatitis, and recurring opportunistic infections (e.g., pneumonia).
• Survival Rate & Treatment: Without treatment, it is fatal early in life. Treatments include enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), and gene therapy.

The Adenosine Deaminase (ADA) Test

• Purpose: Measures the activity of the enzyme, commonly used to diagnose tubercular pleuritis (infection of the pleural fluid around the lungs).
• Significance: Pleural fluid ADA levels > 40 U/I are highly suggestive of tuberculosis in high-prevalence areas.
• Other Causes for Elevation: Elevated ADA levels can also be seen in malignancies (lymphoma), other infections, and empyemas.