Adenosine Deaminase Test

Tuberculosis, Pleural Effusion, Pneumonia, Lymphoma, Infectious Mononucleosis

Adenosine deaminase (ADA) is a protein synthesised by cells throughout the body. ADA functions by activating lymphocytes. The lymphocytes are a kind of white blood cells that help in the immunological response to infections. When the immune system is triggered, with Mycobacterium tuberculosis (the bacteria that causes tuberculosis or TB),

ADA increases in the tissues where bacilli are present.

The adenosine deaminase test detects the level of adenosine deaminase protein in the pleural (tissues that line between lungs and chest wall) fluid. The adenosine deaminase test is used for the diagnosis of pleural tuberculosis infection.

Adenosine Deaminase or ADA, is an enzyme found in human bodies that helps with purine metabolism. The primary purpose of ADA in humans is to keep the immune system established and maintained.

Tuberculosis (TB) is a potentially fatal infectious ailment affecting the lungs. It is transmitted from person to person through droplets released into the air by coughs and sneezes.

This contagious disease has the potential to spread to other parts of your body, including the brain and spine. Mycobacterium tuberculosis is a causative agent of TB.

After a severe, typically long-term tuberculosis infection, an accumulation of fluid in the space between the lining of the lungs and the lung tissue (pleural space) is known as tuberculous pleural effusion.

Pleurae are membranes that line the inside of each lung and cover the chest cavity. During inhalation and expiration, small volumes of pleural fluid continuously lubricate lung movement against these membranes and the membranes against each other. Pleural inflammation (pleurisy or pleuritis) can be due to infection and other diseases.

Tuberculosis can spread to the lungs and pleura, producing chest pain, a persistent cough and shortness of breath. Because these symptoms can be associated with a range of other problems, it's critical to figure out what's causing them. The early diagnosis helps the doctor to begin treatment. However, because there may be a large amount of fluid and very few bacteria present, detecting mycobacteria in pleural fluid can be difficult.

The adenosine deaminase test result isn't specific and can't substitute culture for tuberculosis diagnosis. The adenosine deaminase test results can be positive even when bacteria numbers are low. Therefore, it can help determine whether tuberculosis is the most likely cause.

The adenosine deaminase (ADA) test is a diagnostic test. Still, it is used along with other tests like pleural fluid analysis, acid-fast bacillus (AFB) smear and culture and tuberculosis molecular testing to detect if a person has the Mycobacterium tuberculosis infection.

Although it might take a few days or weeks to complete, culture is the "gold standard" for diagnosing tuberculosis and guiding treatment. The AFB smear and molecular testing are quick tests, but they require many bacteria in the fluid to identify them.

Although the adenosine deaminase test chart is not conclusive, it is a quick test that can show increased levels even when only a few bacteria are present. Until the culture findings are obtained, the adenosine deaminase reports can help the doctor guide treatment.

Other Names Of The Adenosine Deaminase Test

• ADA

What Does the Adenosine Deaminase Test/Measure and Who Is This Prescribed For?

The adenosine deaminase test measures adenosine deaminase protein in the pleural fluid.

This test is part of a series of tests to diagnose or rule out tuberculosis.

The adenosine deaminase test is indicated if the person is in a high-risk group, such as:

• People who have been close to someone who has active infectious tuberculosis.
• Immigrants from parts of the world where tuberculosis is prevalent.
• Children below five years who are positive for the Mantoux test (test for tuberculosis).
• People who work with or are members of high-risk groups, such as the homeless, IV drug users or confined populations, such as hospitalised patients, inmates and nursing home residents.
• Those with weaker immune systems such as HIV/AIDS patients.
• Those with long-term health problems, such as diabetes or kidney illness.
• Immunosuppressant medication users.
• Organ transplant patients.
• Women who are pregnant.
• Elderly people.

The Adenosine Deaminase (ADA) test is done in people with the following symptoms:

• Chronic cough, sometimes with bloody sputum
• Night sweats
• Unexplained weight loss
• Chest pain
• Excessive and frequent diarrhoea
• Widespread skin rashes and allergies
• Uncontrollable fever accompanied by chills

In children, adenosine deaminase values need testing for the following symptoms:

• Developmental issues
• Delayed milestones
• Slow motor development

The presence of more than 43 U/mL of ADA activity in pleural fluid supports the diagnosis of tuberculous pleuritis.

A positive adenosine deaminase test could mean the presence of pleural tuberculosis.

The test, however, only has a sensitivity of 78 per cent. As a result, pleural adenosine deaminase values of less than 43-50 U/mL do not rule out the possibility of tuberculosis pleuritis.

Increased adenosine deaminase range could be due to: 

• Tuberculosis

It's usually a sign of Mycobacterium tuberculosis infection in the pleurae if the adenosine deaminase values in the pleural fluid are significantly more than the adenosine deaminase normal range.

• Sarcoidosis

Sarcoidosis is a condition marked by granulomas. The granulomas are small collections of inflammatory cells commonly in the lungs and lymph nodes. These cells can harm the eyes, skin, heart and other organs. Adenosine deaminase values show an increase in sarcoidosis.

• Pulmonary embolism

A pulmonary embolism occurs when the pulmonary arteries, which carry blood from the heart to the lungs, get blocked. A blood clot forming anywhere in the body and that moves via the bloodstream to the lungs is frequently the origin of the blockage.

• Malignancy

In the case of lung cancer, the pleural fluid may contain adenosine deaminase as a response to the change in the lung tissue.

• Systemic lupus erythematosus

The autoimmune disorder where autoantibodies made by your body destroy your own cells. SLE shows a moderate elevation of adenosine deaminase.

• Lymphoma

Lymphoma is a cancer that involves lymphatic tissue. When the abdominal lymph nodes are involved, the peritoneal fluid can have an increase in ADA.

If the adenosine deaminase range is low, the person is unlikely to have tuberculosis. But the possibility cannot be ruled out based on this test alone.

The adenosine deaminase test cannot diagnose M. tuberculosis infection. The adenosine deaminase test results cannot be used to detect drug-resistant tuberculosis.

For the adenosine deaminase test procedure, a sample of pleural fluid is essential. A healthcare professional collects pleural fluid using a method called thoracentesis. Thoracentesis is a process in which a healthcare professional collects a sample of pleural fluid using a syringe and needle.

Test Preparation

The Adenosine Deaminase test does not need any special preparation. However, certain medicines and substances can change adenosine deaminase values, which could show up in the test results.

Make sure to inform the doctor and follow the advice before taking the test. The doctor will provide instructions based on the medical situation.

Test Inclusions: What are the Parameters Included in the Test?

The adenosine deaminase test results include only one parameter. It shows:

• Increase in adenosine deaminase values
• Decrease in adenosine deaminase values

How Frequently Should You Take This Test?

The doctor will start with the treatment if pleural tuberculosis is confirmed by the adenosine deaminase test.

Treatment for tuberculosis lasts for six to nine months. The doctor will order a repetition of the adenosine deaminase test if new symptoms appear.

If the doctor suspects the previous report was false-negative or false-positive, he may ask for a repetition of the test after 15 days.

The adenosine deaminase test is repeated within one month with another sample if adenosine deaminase test results are negative and symptoms of tuberculosis persist.