ADA in pleural fluid

Q: What's the utility of measuring adenosine deaminase (ADA) in pleural fluid? 

 
Answer: To differentiate between malignant and tuberculous pleurisy 

 If a situation arises where the pleural fluid is exudative, lymphocytic, but initial cytology, smear, and culture fails to document tuberculosis or malignancy, ADA can be relied on with good confidence. The usual cutoff point to make that distinction is at around 35-40 U/L. ADA is usually less than 40 U/L in malignant pleural effusions, more than 35 to 50 U/L in tuberculous pleural effusions. 

 Said that interpretation of ADA should be done in connection with clinical history, physical exam, geographic locations, and local experts.

#pulmonary

#infectious-diseases 

#oncology

​#laboratory science

References: 

1.  Liang QL, Shi HZ, Wang K, et al. Diagnostic accuracy of adenosine deaminase in tuberculous pleurisy: a meta-analysis. Respir Med 2008; 102:744. 

2.  Ogata Y, Aoe K, Hiraki A, et al. Is adenosine deaminase in pleural fluid a useful marker for differentiating tuberculosis from lung cancer or mesothelioma in Japan, a country with intermediate incidence of tuberculosis? Acta Med Okayama 2011; 65:259. 

3. Biswas B, Sharma SK, Negi RS, et al. Pleural effusion: Role of pleural fluid cytology, adenosine deaminase level, and pleural biopsy in diagnosis. J Cytol 2016; 33:159. 

4.  Sivakumar P, Marples L, Breen R, Ahmed L. The diagnostic utility of pleural fluid adenosine deaminase for tuberculosis in a low prevalence area. Int J Tuberc Lung Dis 2017; 21:697.