The role of the Adenosine Deaminase test

Posted by Doctor of Hematology - Blood Transfusion - Laboratory Department - Vinmec Ha Long International General Hospital.

Adenosine Deaminase (ADA) is a protein produced by cells throughout the body and is involved in the activation of lymphocytes, a type of white blood cell that plays an important role in the immune response to infection coincide. A test that measures the amount of Adenosine Deaminase in the pleural fluid helps diagnose pleural tuberculosis.

Adenosine deaminase is an enzyme found in mammals that acts on the purine base metabolism pathway. Reduce Adenosine to catalyze the reaction to form inosine and ammonia. Among congenital immunodeficiency diseases, B and T lymphocytes become dysfunctional due to lack of this enzyme (ADA deficiency).
ADA enzymes are produced from many cell types but mainly from activated T lymphocytes. This enzyme breaks down Adenosine to Inosine.
Its main function in humans is the development and maintenance of the immune system. However, the full physiological role of ADA is still poorly understood.
Although the ADA test is nonspecific and cannot substitute for culture isolates for the diagnosis of TB, it can be used as an adjunct to the identification of patients with symptoms of TB. .

The Adenosine deaminase (ADA) test is not a diagnostic test, but it may be used in conjunction with other tests such as pleural fluid analysis, direct antacid bacterioscopy (AFB), stool culture The establishment, or TB molecular biology test, to help identify people infected with the TB bacteria pulmonary TB (pleurae)
Culture isolates are considered the "gold standard" for TB diagnosis and treatment guidelines. , but it can take days to weeks to get results Molecular biology and direct staining AFB tests, but the test requires a sufficient number of microorganisms present in the substance. fluid to detect them The presence of pleural fluid can be an important factor in detecting M.tuberculosis because very low numbers of bacteria can be present in a large volume of fluid. Although the ADA test is nonspecific, it is a rapid test and can be elevated even when some bacteria are present. used to help guide treatment until isolated culture results are available.
The ADA test is used as an adjunct to differentiate or exclude pleural TB.

ADA testing may be ordered when the patient has pleural fluid and symptoms suggest a M.tuberculosis infection. Signs and symptoms of Tuberculosis (TB) affecting the lungs may include:
Chronic cough, sometimes with bloody sputum; Fever, chills; Night sweats; Unexplained weight loss; Weak; Chest pain. This test may be ordered as a test to rule out TB, especially those in high-risk groups, such as:
People in close contact with people with active infectious TB , Immigrants from areas of the world where TB incidence is high, Children under 5 years of age. Children with a positive screening test for TB. Workers who have contact with groups with high rates of infection, such as homeless drug users or restricted populations, such as hospitalized patients, prisoners, and nursing home residents, People with weakened immune systems such as: People with HIV/AIDS, People with chronic medical conditions, including diabetes and kidney disease organ transplant recipients, and others taking immunosuppressive drugs; Pregnant women; Elderly.

Test Adenosine deaminase (ADA): Diagnosis of pleural effusion due to TB when ADA in blood and pleural fluid are both elevated, diagnostic threshold is 40-60u/L. Specificity 81 - 94%, sensitivity 91 - 100%, negative diagnosis 89 - 100%, positive 84 - 93%.
If Adenosine Deaminase (ADA) is markedly increased in the pleural fluid in a person with symptoms suggestive of tuberculosis, the person is likely to have M.tuberculosis in the pleura. This is especially true when there is a high prevalence of TB in a geographic area.
If the ADA result is only mildly or moderately elevated, and in an area with low TB prevalence, the person may have TB or may have another disease such as cancer (especially lymphoma), pulmonary embolism , sarcoidosis, or systemic lupus erythematosus ....
If the ADA result is low, the person does not have pleural TB.
If ADA is markedly increased in the fluid in another part of the body (peritoneal fluid, cerebrospinal fluid, etc.), it is likely that that part is infected with TB.
To register for examination and treatment at Vinmec International General Hospital, you can contact Vinmec Health System nationwide, or register online HERE.
SEE ALSO:
Diagnosis of AFB-negative childhood TB by scorecard How dangerous and curable is pulmonary TB What is the difference between lymph node TB and pulmonary TB?