AsseyMethod: Enzymatic
Abbrevation: ADA
Sector: Biochemistry
SampleType: S,PE,CSF,BF
S.Vol: 0.3
Transport: at 2-8˚c, -20˚c
Storage: 5 days at 2-8˚c 1 month at -20˚c
Test Name: Adenosine deaminase
Normal Range: CSF:up to 5 serum:10-25
o 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 a doctor suspects that someone with chest pain, coughing, and/or difficulty breathing has tuberculosis that has spread from their lungs to the pleurae (lining around the lungs)
A volume of pleural fluid is collected by a doctor using a procedure called thoracentesis; other body fluids are collected using other procedures
None required
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.
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 occurs most commonly in the lungs, and it can spread into the 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. The ADA test is not as accurate as a culture for diagnosing TB, however results will be available much quicker so it can be used as an additional 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.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.