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Adenosine Deaminase

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Also known as: ADA
Formal name: Adenosine Deaminase, Fluid

At a Glance

Why Get Tested?

To help detect or rule out a Mycobacterium tuberculosis infection in pleural fluid in order to assist in the diagnosis of tuberculosis; rarely to detect the infection in other body fluids such as peritoneal fluid or cerebrospinal fluid (CSF)

When to Get Tested?

When a doctor suspects that someone with chest pain, coughing, and/or difficulty breathing has tuberculosis that has spread to their pleurae (lining around the lungs)

Sample Required?

A volume of pleural fluid is collected by a doctor using a procedure called thoracentesis; other body fluids are collected using other procedures

Test Preparation Needed?


The Test Sample

What is being tested?

Adenosine deaminase (ADA) is a protein that is produced by cells throughout the body and is associated with the activation of lymphocytes, a type of white blood cell that plays a role in the immune response to infections. Conditions that trigger the immune system, such as an infection by Mycobacterium tuberculosis, the bacteria that causes tuberculosis (TB), may cause increased amounts of ADA to be produced in the areas where the bacteria are present. This test measures the amount of adenosine deaminase present in pleural fluid in order to help diagnose a tuberculosis infection of the pleurae.Thumbnail diagram of respiratory system

Pleurae are membranes that cover the chest cavity and the outside of each lung. Small amounts of pleural fluid are continuously produced to lubricate the movement of the lungs against these membranes and the membranes against each other during inhalation and exhalation. A variety of conditions and diseases, including infection, can cause inflammation of the pleurae (pleurisy or pleuritis) and can lead to excessive pleural fluid accumulation (pleural effusion).

Tuberculosis can spread into the lungs and pleurae, causing symptoms such as chest pain, chronic cough, and shortness of breath. Since these symptoms may also be seen with a variety of other conditions, it is important to determine the cause as rapidly as possible in order to properly treat the affected person. Detecting mycobacteria in pleural fluid can be difficult because there may be a large volume of fluid and very low numbers of bacteria present. Though the ADA test is not specific and does not replace the culture for diagnosing TB, it may be positive even when numbers of bacteria are very low and can be used as an adjunct test to help determine whether tuberculosis is the likely source of a person's symptoms.

How is the sample collected for testing?

A sample of pleural fluid is collected by a doctor with a syringe and needle using a procedure called thoracentesis. Rarely, other body fluid samples, such as peritoneal or CSF, are collected using procedures specific to the fluid type.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Herchline, T. and Chavis, P. (Updated 2012 March 22). Tuberculosis. Medscape Reference [On-line information]. Available online at through Accessed April 2012.

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Hanson, K. (Updated 2011 March). Mycobacterium tuberculosis – TB. ARUP Consult [On-line information]. Available online at through Accessed April 2012.

Baba, K. et. al. (2008 July). Adenosine Deaminase Activity Is a Sensitive Marker for the Diagnosis of Tuberculous Pleuritis in Patients with Very Low CD4 Counts. PLoS ONE v 3(7): e2788 [On-line information]. Available online at through Accessed April 2012.

Laniado-Laborín, R. (2005 Feberuary). Adenosine Deaminase in the Diagnosis of Tuberculous Pleural Effusion, Is It Really an Ideal Test? A Word of Caution. CHEST v 127 (2) 417-418 [On-line information]. Available online at through Accessed April 2012.

Jiménez Castro, D. et. al. (2003 February 1). Diagnostic value of adenosine deaminase in nontuberculous lymphocytic pleural effusions. Eur Respir J 2003; 21: 220–224 [On-line information]. Available online at through Accessed April 2012.

Gupta, B. et. al. (2010 October). Adenosine Deaminase Levels in CSF of Tuberculous Meningitis Patients. J Clin Med Res. 2010 October; 2(5): 220–224. [On-line information]. Available online at through Accessed April 2012.

(Reviewed 2008 February). Adenosine deaminase deficiency. Genetics Home Reference [On-line information]. Available online at through Accessed April 2012.

Hershfield, M. (Updated 2011 December 22). Adenosine Deaminase Deficiency. GeneReviews [On-line information]. Available online at through Accessed April 2012.

(© 1995-2012). Test ID: FADA Adenosine Deaminase, Fluid. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at through Accessed April 2012.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 50-53.