Diagnosis of Pulmonary and Extra-pulmonary Tuberculosis: Role of Adenosine Deaminase Levels in Different Body Fluids

Abstract

Background: Tuberculosis (TB) is one of the major public health problems, particularly in developing countries. There are many tools to diagnose TB, one of them is the estimation of the level of adenosine deaminase (ADA) in various fluids in the body. Objectives: To find the role of ADA levels in 4 different types of body fluids to diagnose TB and extra-pulmonary TB. Materials and Methods: This prospective study was conducted in the 3 main hospitals in Anbar governorate, Iraq for one year from July 2019 to June 2020. Four types of body fluids [serum samples, pleural fluid, ascetic fluid, and cerebrospinal fluid (CSF)] were collected from patients who were suspected of having TB. The levels of ADA were measured by ELISA. An accurate diagnosis of TB was done by Genexpert real-time polymerase reaction (PCR). The results were compared according to PCR findings. Results: Out of 176 patients, there were 31 patients were proved to be positive, for TB by Genexpert real-time PCR. The highest mean level of ADA in positive TB cases by PCR was in the pleural fluid (58.258±2.707), and the last was in the serum. There was a highly statistically significant difference between the ADA levels in all 4 body fluids between the positive and negative TB cases (P-value= 0.000). In the positive cases, the sensitivity of ADA levels in the serum, CSF, pleural fluid, and ascetic fluid were found to be 40%, 81%, 96%, and 94% respectively and the specificity was found to be 88%, 72%, 94%, and 90% respectively.  Conclusion: The ADA levels in all 4 body fluids were highly statistically different between TB negative and positive cases diagnosed by PCR. However, they had different sensitivity and specificity levels.

Keywords

• adenosine deaminase
• tuberculosis
• serum
• cerebrospinal fluid
• pleurisy
• ascites