BiochemicalPulmonology

ADA (Adenosine Deaminase) Levels

Normal Range
< 40 U/L (Fluid), < 20 U/L (Serum)
Sample Type
Pleural Fluid
Fasting
No
Unit
U/L

Function

Adenosine Deaminase (ADA) is an enzyme involved in purine metabolism. Its primary biological role is the proliferation and differentiation of lymphocytes, particularly T-lymphocytes. Because ADA activity increases significantly during a cellular immune response, it serves as a surrogate marker for diseases that trigger T-cell activation.

Why it is Ordered

The ADA test is most frequently performed on pleural fluid, ascitic fluid, or cerebrospinal fluid (CSF) to help diagnose Extrapulmonary Tuberculosis (TB). It is a rapid, cost-effective alternative to culture, which can take weeks. It is also used in serum to help investigate certain immune deficiencies or liver diseases.

Associated Conditions

  • Tuberculous Pleurisy: Very high ADA levels in pleural fluid are highly indicative of TB.
  • Malignancy: Certain cancers, such as lymphomas, can cause elevated ADA.
  • Rheumatoid Arthritis: Can cause elevated ADA in synovial fluid.
  • ADA Deficiency: A rare genetic condition leading to Severe Combined Immunodeficiency (SCID).

Check Your Result

Check Your Result

Interactive
U/L

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

ADA is a highly sensitive but not perfectly specific test. High levels can occur in bacterial empyema, lupus, or certain lymphomas, mimicking the profile of Tuberculosis. Conversely, very early-stage TB might yield a lower-than-expected result. Clinical correlation with imaging and other markers is essential.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for ADA (Adenosine Deaminase) Levels:

Research & Guidelines

Related Indicators

Pleural Fluid - Biochemical Analysis

View Range

Pleural Fluid for Amylase

View Range
DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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