Pleural Adenosine Deaminase Levels Research Articles

The Impact Profile and Adenosine Deaminase of Age and Female Sex on Its Level in Patients with Pleural Effusion Syndrome

Background: Pleural fluid analysis and closed pleural biopsy are integral parts in the investigative work up of an exudative pleural effusion. For diagnosis of tuberculous pleural effusion (TPE), the yield of pleural fluid culture for mycobacteria is low at about 36%. Objective: To evaluate the levels of adenosine deaminase (ADA) in the pleural fluids (P-ADA) of untreated and non-surgically manipulated female and male adult patients with several confirmed causes of PES. Methods: This was an observational study conducted at dept. of Internal Medicine, 250 Bedded Mohammad Ali Hospital, Bogura, Bangladesh from January to June 2023. 100 pleural fluid samples from 100 patients with proven causes of PES. The sample size was appropriate according to the study design. Written consent was obtained from all patients. It was precise enough to calculate descriptive and inferential statistics on type I and II errors, effect size, standard deviation, and was not influenced by administrative issues and costs. Results: 100 patients summarize the prevalence of the causes of PES and the demographic characteristics. TB was the most prevalent cause of PES (28/100, 28%). Most prevalent male sex was in the lymphoma group (4/0, 100%). None of the five patients with lymphoma were female. When the frequencies were compared for males and females, only adenocarcinoma and lymphoma were significant (chi- square tests, p=0.0021 and p=0.0003, respectively). The causes, prevalence, and median P-ADA (n/%/U/L) were tuberculosis (28/28.0/42.0), adenocarcinoma (24/24.0/9.75), transudate (21/21.0/6.85), simple parapneumonic pleural effusions (PPE; 10/10.0/9.38), complicated PPE/empyema (5/5.0/32.9), lymphoma (4/4.0/401.2), squamous cell carcinoma (4/4.0/13.11), and others (4/4/15.2). For P-ADA, Dunn's post hoc test revealed significance for tuberculosis vs. transudates, vs. simple PPE, and vs. adenocarcinoma (all P<0.05), and not significant for CPPE/empyema, lymphoma, SCC, and others (all P>0.05). For age, Dunn’s post hoc test revealed significance for tuberculosis vs. transudates, vs. simple PPE, and vs. adenocarcinomas (all P<0.05). Sex was not significant in the overall PES group (Chi=0.062, P=0.8028). Kendall's correlation of the relationship between P-ADA and age for pleural tuberculosis (n=26) was significant after 1000 iterations with bootstrap for 95% CI (Tau=-0.213, 95% CI - 0.449-0.0833, P=0.0490). A negative LOESS regression was evident between P-ADA and age >40 years. Conclusions: Evaluation of pleural ADA levels is useful for diagnosing pleural tuberculosis, while sex is not. A negative and significant relationship between P- ADA level and age >40 years was evident.

Profile of Adenosine Deaminase and the Impact of Age and Female Sex on Its Level in 157 Patients with Pleural Effusion Syndrome

Background: The profile of adenosine deaminase enzyme and the impact of demographic data on its level are important in patients with pleural effusion syndrome (PES). Objective: To evaluate the levels of adenosine deaminase (ADA) in the pleural fluids (P-ADA) of untreated and non-surgically manipulated female and male adult patients with several confirmed causes of PES. Methods: This observational, retrospective cohort study in the State of Rio de Janeiro, Brazil, involved 157 patients. The study variables were age, total P-ADA determined using a commercial kit, and male and female sex. Results: The causes, prevalence, and median P-ADA (n/%/U/L) were tuberculosis (44/28.0/42.0), adenocarcinoma (37/24.0/9.75), transudate (33/21.0/6.85), simple parapneumonic pleural effusions (PPE; 15/10.0/9.38), complicated PPE/empyema (8/5.0/32.9), lymphoma (7/4.0/401.2), squamous cell carcinoma (7/4.0/13.11), and others (6/4/15.2). For P-ADA, Dunn's post hoc test revealed significance for tuberculosis vs. transudates, vs. simple PPE, and vs. adenocarcinoma (all P<0.05), and not significant for CPPE/empyema, lymphoma, SCC, and others (all P>0.05). For age, Dunn’s post hoc test revealed significance for tuberculosis vs. transudates, vs. simple PPE, and vs. adenocarcinomas (all P<0.05). Sex was not significant in the overall PES group (Chi=0.062, P=0.8028). Kendall's correlation of the relationship between P-ADA and age for pleural tuberculosis (n=41) was significant after 1000 iterations with bootstrap for 95% CI (Tau=-0.213, 95% CI - 0.449-0.0833, P=0.0490). A negative LOESS regression was evident between P-ADA and age >40 years. Conclusions: Evaluation of pleural ADA levels is useful for diagnosing pleural tuberculosis, while sex is not. A negative and significant relationship between P-ADA level and age >40 years was evident.

Factors associated with negative pleural adenosine deaminase results in the diagnosis of childhood pleural tuberculosis

BackgroundUntil now, the influential factors associated with pleural adenosine deaminase (ADA) activity among children remain unclear. This retrospective study was therefore conducted aiming to investigate the factors associated with negative pleural ADA results in the diagnosis of childhood pleural tuberculosis (TB).MethodsBetween January 2006 and December 2019, children patients with definite or possible pleural TB were recruited for potential analysis. Then, patients were stratified into two categories: negative pleural ADA results group (experimental group, ≤40 U/L) and positive pleural ADA results group (control group, > 40 U/L). Univariate and multivariate logistic regression analyses were performed to estimate risk factors for negative pleural ADA results.ResultsA total of 84 patients with pleural TB were recruited and subsequently classified as experimental (n = 17) and control groups (n = 67). Multivariate analysis (Hosmer–Lemeshow goodness-of-fit test: χ2 = 1.881, df = 6, P = 0.930) revealed that variables, such as chest pain (age-adjusted OR = 0.0510, 95% CI: 0.004, 0.583), pleural total protein (≤45.3 g/L, age-adjusted OR = 27.7, 95% CI: 2.5, 307.7), pleural lactate dehydrogenase (LDH, ≤505 U/L, age-adjusted OR = 59.9, 95% CI: 4.2, 857.2) and blood urea nitrogen (≤3.2 mmol/L, age-adjusted OR = 32.0, 95% CI: 2.4, 426.9), were associated with negative pleural ADA results when diagnosing childhood pleural TB.ConclusionOur findings demonstrated that chest pain, pleural total protein, pleural LDH, and blood urea nitrogen were associated with a negative pleural ADA result for the diagnosis of pleural TB among children. When interpreting pleural ADA levels in children with these characteristics, a careful clinical assessment is required for the pleural TB diagnosis.

Laboratory and radiological discrimination between tuberculous and malignant pleural effusions with high adenosine deaminase levels.

Background/AimsPleural fluid adenosine deaminase (ADA) levels are useful in discriminating tuberculous pleural effusions (TPEs) from malignant pleural effusions (MPEs). However, some patients with MPE exhibit high-ADA levels, which may mimic TPEs. There is limited data regarding the differential diagnosis between high-ADA MPE and high-ADA TPE. This study aimed to identify the predictors for distinguishing high-ADA MPEs from high-ADA TPEs.MethodsPatients with TPE and MPE with pleural fluid ADA levels ≥ 40 IU/L were included in this study. Clinical, laboratory, and radiological data were compared between the two groups. Independent predictors and their diagnostic performance for high-ADA MPEs were evaluated using multivariate logistic regression analysis and receiver operating characteristic curve.ResultsA total of 200 patients (high-ADA MPE, n = 30, and high-ADA TPE, n = 170) were retrospectively included. In the multivariate analysis, pleural fluid ADA, pleural fluid carcinoembryonic antigen (CEA), and pleural nodularity were independent discriminators between high-ADA MPE and high-ADA TPE groups. Using pleural ADA level of 40 to 56 IU/L (3 points), pleural CEA level ≥ 6 ng/mL (6 points), and presence of pleural nodularity (3 points) for predicting high-ADA MPEs, a sum score ≥ 6 points yielded a sensitivity of 90%, specificity of 96%, positive predictive value of 82%, negative predictive value of 98%, and area under the receiver operating characteristic curve of 0.965.ConclusionsA scoring system using three parameters may be helpful in guiding the differential diagnosis between high-ADA MPEs and high-ADA TPEs.

Diagnostic utility of serum adenosine deaminase level in the diagnosis of pulmonary tuberculosis

This study was conducted to evaluate the role of serum adenosine deaminase (ADA) level in the diagnosis of pulmonary tuberculosis (TB) and its relationship with clinical, radiological, and laboratory parameters. This study was performed on 70 individuals: 60 patients with tuberculous and nontuberculous pulmonary diseases and 10 apparently healthy individuals as a control group. The participants were divided into four groups: group I included 30 patients with active pulmonary TB who were subdivided into group IA, which included 20 patients with sputum smear-positive pulmonary TB, and group IB, which included 10 patients with sputum smear-negative pulmonary TB (culture positive); group II included 10 patients with tuberculous pleural effusion; group III included 20 patients with nontuberculous lung diseases (five cases with pneumonia, five cases with pyogenic lung abscess, five cases with bronchiectasis, three cases with lung cancer, and two cases with mesothelioma); and group IV included 10 apparently healthy individuals as a control group. Patients were subjected to history taking, clinical examination, plain chest radiography posterior–anterior view, three consecutive sputum smears for acid-fast bacilli (AFB), sputum culture for AFB using BACTEC TB-460 system in group IB, laboratory investigations, tuberculin skin test, serum ADA level evaluation in all participants, and pleural ADA level evaluation in cases of tuberculous pleural effusion. Serum ADA showed high percentage positivity (90%) in the diagnosis of pulmonary TB, followed by tuberculin skin test (83.3%), chest radiography (73.3%), erythrocyte sedimentation rate (70%), sputum for AFB (66.6%), toxic symptoms (53.3%), and hemoptysis (36.3%). Serum ADA sensitivity and specificity at cut-off point 30.15 μ/l were 95 and 86.7%, respectively, with a positive predictive value of 90.5%, negative predictive value of 92.2%, and accuracy of 91.4%. Serum ADA level shows higher percentage positivity compared with clinical, radiological, and laboratory parameters in the diagnosis of pulmonary TB.

Pleural effusion adenosine deaminase: a candidate biomarker to discriminate between Gram-negative and Gram-positive bacterial infections of the pleural space

OBJECTIVES:Delay in the treatment of pleural infection may contribute to its high mortality. In this retrospective study, we aimed to evaluate the diagnostic accuracy of pleural adenosine deaminase in discrimination between Gram-negative and Gram-positive bacterial infections of the pleural space prior to selecting antibiotics.METHODS:A total of 76 patients were enrolled and grouped into subgroups according to Gram staining: 1) patients with Gram-negative bacterial infections, aged 53.2±18.6 years old, of whom 44.7% had empyemas and 2) patients with Gram-positive bacterial infections, aged 53.5±21.5 years old, of whom 63.1% had empyemas. The pleural effusion was sampled by thoracocentesis and then sent for adenosine deaminase testing, biochemical testing and microbiological culture. The Mann-Whitney U test was used to examine the differences in adenosine deaminase levels between the groups. Correlations between adenosine deaminase and specified variables were also quantified using Spearman’s correlation coefficient. Moreover, receiver operator characteristic analysis was performed to evaluate the diagnostic accuracy of pleural effusion adenosine deaminase.RESULTS:Mean pleural adenosine deaminase levels differed significantly between Gram-negative and Gram-positive bacterial infections of the pleural space (191.8±32.1 U/L vs 81.0±16.9 U/L, p<0.01). The area under the receiver operator characteristic curve was 0.689 (95% confidence interval: 0.570, 0.792, p<0.01) at the cutoff value of 86 U/L. Additionally, pleural adenosine deaminase had a sensitivity of 63.2% (46.0-78.2%); a specificity of 73.7% (56.9-86.6%); positive and negative likelihood ratios of 2.18 and 0.50, respectively; and positive and negative predictive values of 70.6% and 66.7%, respectively.CONCLUSIONS:Pleural effusion adenosine deaminase is a helpful alternative biomarker for early and quick discrimination of Gram-negative from Gram-positive bacterial infections of the pleural space, which is useful for the selection of antibiotics.

The comparative value of pleural fluid adenosine deaminase and neopterin levels in diagnostic utility of pleural tuberculosis.

The aim of the present study was to evaluate and compare the diagnostic accuracy of pleura levels of adenosine deaminase (ADA) and neopterin for the differential diagnosis of pleural tuberculosis (TP). The study included 50 patients with TB, 27 patients with malignancies, and 24 patients with pleural effusion of non-tuberculous and non-malignant origin as controls. ADA and neopterin levels in pleural fluid were measured by spectrofotometric and ELISA method, respectively. Pleural neopterin levels were significantly higher in patients with pleural TB than patients with malignancy (p< 0.001). Pleural ADA levels were significantly higher in patients with pleural TB than patients with malignancy (p< 0.001) and patients with benign non-tuberculosis effusions (p< 0.001). The mean levels of ADA and neopterin in pleural effusion were evaluated according to their underlying diseases for the diagnostic accuracy. As for pleural TB receiving operating characteristic curves identified the following results; The best cut-off value for pleural neopterin was 4.7 U/L and yielded a sensitivity and specificity of 86% and 72.55%, respectively. Taking a cut-off value of 42 U/L for pleural ADA, the sensitivity and the specificity were found to be 88% and 68.63%, respectively. In the diagnosis of pleural TB pleural neopterin level has a comparable sensitivity to pleural ADA activity. Both markers may find a place as a routine investigation in the coming days for early detection of TB. However, these tests should not be considered an alternative to biopsy and culture.

Role of thoracentesis in the management of tuberculous pleural effusion

BackgroundTuberculous pleural effusion (TPE) is the second most common form of extrapulmonary tuberculosis (EPTB). Up to 50% after treatment complicated with pleural thickening. Pleural biopsy has been considered the gold standard in diagnosis of TPE but it is invasive, so that pleural fluid markers of TPE have been extensively evaluated as an alternative to pleural biopsy. Thoracentesis for measuring these fluid markers is important. AimAssessing the value of diagnostic thoracentesis (by measuring pleural adenosine deaminase levels) and role of therapeutic thoracentesis in preventing pleural thickening. Subjects and methods10 cases with transudative pleural effusion and 45 cases with already diagnosed exudative effusion (30 cases of TPE, and 15 cases of Malignant PE) were included. 50ml pleural fluid samples were aspirated and sent for measuring ADA levels. The 30 cases of TPE were classified into 2 equal groups the 1st group started 6months anti tuberculous therapy plus repeated thoracentesis while the 2nd started anti tuberculous therapy only. Chest CT scan was done after 2 and 6months for assessment of pleural effusion and pleural thickening. ResultsPatients with tuberculous pleural effusion had higher pleural effusion ADA levels (mean±SD 68.51±24.06) than those with malignant pleural effusion (mean±SD 25.47±12.09) or transudative pleural effusion (mean±SD 16.58±2.93) and these levels had highly a significant difference (P-value <0.001). Also, there was a significant difference (P-value <0.05) between levels of ADA in malignant and transudative pleural effusion. Using a cut-off point of the pleural fluid ADA (30.49IU/L) with AUC of 96.7 (sensitivity 96.7%, specificity 84%, NPV 88%, PPV 95% and accuracy 91%) discrimination between tuberculous and other causes of pleural effusion occurred. Regarding the pleural thickening, after 2months of ttt, in group I, 3 cases developed pleural thickening, while in group II, 9 cases developed thickening. After 6months, there was one case of pleural thickening in group I, while in group II, 5 cases developed pleural thickening. And there was a significant difference (P value <0.05) between both groups, after 2 and 6months of treatment. ConclusionsThoracentesis is very important in the diagnosis of TPE either through diagnostic thoracentesis by measuring fluid markers such as ADA or therapeutic thoracentesis which is not only important for relieving dyspnea but also in preventing occurrence of pleural thickening that complicated cases of TPE.

Factors Affecting Pleural Adenosine Deaminase Level in Tuberculous Pleural Effusion

SESSION TYPE: Pleural Biomarkers

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?

The objective of this study was to evaluate the utility of the determination of adenosine deaminase (ADA) level in pleural fluid for the differential diagnosis between tuberculous pleural effusion (TPE) and malignant pleural effusion (MPE) in Japan, a country with intermediate incidence of tuberculosis (TB). We retrospectively reviewed the clinical records of 435 patients with pleural effusion and investigated their pleural ADA levels as determined by an auto analyzer. ROC analysis was also performed. The study included patients with MPE (n＝188), TPE (n＝124), benign nontuberculous pleural effusion (n＝94), and pleural effusion of unknown etiology (n＝29). The median ADA level in the TPE group was 70.8U/L, which was significantly higher than that in any other groups (p＜0.05). The area under the curve (AUC) in ROC analysis was 0.895. With a cut-off level for ADA of 36U/L, the sensitivity, specificity, positive predictive value, and negative predictive value were 85.5%, 86.5%, 69.7%, and 93.6%, respectively. As many as 9% of patients with lung cancer and 15% of those with mesothelioma were false-positive with this ADA cutoff setting. Although the ADA activity in pleural fluid can help in the diagnosis of TPE, it should be noted that some cases of lung cancer or mesothelioma show high ADA activity in geographical regions with intermediate incidence of TB, in contrast to high prevalence areas.

Concurrent measurement of adenosine deaminase and dipeptidyl peptidase IV activity in the diagnosis of tuberculous pleural effusion

Measurement of pleural fluid adenosine deaminase (ADA) levels aids diagnosing tuberculous pleural effusion (TPE). Dipeptidyl peptidase IV (DPP) enzyme is closely related to ADA. Our aim was to determine the value of concurrent measurement of these T-cell–associated enzymes, ADA and DPP levels in the diagnosis of TPE. Patients with pleural effusion were grouped as TPE, parapneumonic, malignant, congestive heart failure related, and miscellaneous pleural effusions. Pleural and serum ADA and DPP levels were measured. Pleural and serum levels of ADA and pleural DPP were higher in TPE group than the rest. In 7 patients, pleural biopsy revealed granulomatous pleuritis. All of these patients had TPE and had elevated serum and pleural ADA levels. Serum and pleural ADA or DPP levels and pleural ADA and DPP levels correlated with each other. Selecting cutoff values of 40 and 27 IU/L for pleural ADA and DPP, respectively, the sensitivity of concurrent measurement of both enzymes was 77%, specificity 94%, and diagnostic efficiency 91%. ADA and DPP play an important role in tuberculous immunopathogenesis. The utility of DPP in the diagnosis of TPE has never been determined before. Concurrent measurement of ADA–DPP can aid in diagnosing TPE with higher specificity, sensitivity, and efficiency.

Relationship between Pleural Adenosine Deaminase Level and Patterns of Pleural Enhancement in Patients with a Tuberculous Pleural Effusion on CT Scan

Poster: ECR 2012 / C-0034 / Relationship between pleural adenosine deaminase level and patterns of pleural enhancement in patients with tuberculous pleural effusion on CT scan by: S. M. Yoo1, H. Y. Lee2; 1Bundang/KR, 2Seoul/KR

Role of biochemical tests in the diagnosis of exudative pleural effusions

Objectives: To examine the diagnostic utility of pleural adenosine deaminase (PADA), pleural lactate dehydrogenase (PLDH), and several other biochemical tests in bronchogenic carcinoma and malignant mesothelioma, and to compare biochemical characteristics of their fluid with nonmalignant pleural effusions. Design and methods: This study consisted of 226 patients diagnosed with malignant (75), tuberculous (65), and parapneumonic pleural effusions (86). We examined the following biochemical parameters in the pleural fluid and serum: adenosine deaminase, lactate dehydrogenase, glucose level, protein level, pleural fluid/serum ADA ratio (P/S ADA), P/S LDH ratio, and P/S protein ratio. Results: Parapneumonic pleural effusions had a significantly higher level of PLDH and of P/S LDH than malignant and tuberculous pleural effusions ( P = 0.000), and malignant pleural effusions had a higher level of PLDH than tuberculous pleural effusions. Tuberculous and parapneumonic effusions had significantly higher levels of PADA than those of malignant effusions ( P = 0.000). When the 54 patients having bronchogenic carcinoma were compared to the remaining 21 mesothelioma patients, the former had a lower median level of PADA ( P = 0.001) with a higher level of PLDH ( P = 0.05). Conclusion: Our results show that high pleural LDH and low PADA levels are suggestive of pleural effusion due to bronchogenic carcinoma, whereas high levels of PADA alone can be indicative of tuberculous pleural effusion and high levels of both markers can show complicated parapneumonic effusions or empyema.

Pleural adenosine deaminase levels in tuberculous pleurisy--its diagnostic performance under the different prevalences in the different age of population

In the diagnosis of pleural effusion, tuberculous pleurisy should always be considered because the prevalence of tuberculosis in Japan remains high. The measurement of adenosine deaminase (ADA) levels in pleural fluid is useful for the diagnosis of the tuberculous pleurisy because of its high sensitivity and specificity. However, no studies have addressed the post-test probability (= positive predictive value; PPV) of the test. Since the PPV depends on the pre-test probability (= prevalence) of the tuberculous pleurisy that varies with age, we have retrospectively evaluated the PPV in the different age population; the young (-35 years of age), the middle (36-65 years), and the old (66-years). A total of 208 data sets were collected; the tuberculosis (n = 52), malignancy (n = 34), non-specific infection (n = 31), transudates (n = 45), the others (n = 36), and unknown causes (n = 10). It was found that 1) the prevalence of tuberculous pleurisy was decreased with age, (70% in the young, 28.7% in the middle, and 8.5% in the old), 2) the PPV was the lowest in the old (53.8%), while the highest in the young (95.0%), and 3) no significant correlation was found between age and the ADA activity in pleural effusion.

Raised Pleural Adenosine Deaminase: Does it Mean Tuberculosis?-To the Editor

Dr. Sahoo's letter raises two interesting objections to the determination of pleural adenosine deaminase (PADA) for diagnosis of tuberculous pleurisy. First, he believes that the significance of this parameter is questionable in view of the wide range of diagnostic cutoff points used in the various studies that have supported the use of PADA (25 to 50 U/L). Second, he points out that there have been reports1,2 of high PADA levels being an insufficiently specific criterion for diagnosis of tuberculous pleurisy.

Raised Pleural Adenosine Deaminase: Does it Mean Tuberculosis?

We read with interest, the article by Valdes et al 1. Valdes L. San Jose E. Alvarez D. Sarandeses A. Pose A. Chomon B. et al. Diagnosis of tuberculous pleurisy using the biologic parameters adenosine deaminase, lysozyme, and interferon gamma. Chest. 1993; 103: 458-465 Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar who conclude that raised pleural adenosine deaminase (PADA) and interferon (IFN) are both useful for early diagnosis of tuberculous pleural effusions (note that determining PADA is much less expensive). Since its initial description by Piras et al, 2. Piras M.A. Gakis C. Budroni M. Andreoni G. Adenosine deaminase activity in pleural effusions: an aid to differential diagnosis. Br Med J. 1978; ii: 1751-1752 Crossref Scopus (166) Google Scholar raised PADA has been assumed as a great/useful diagnostic tool for tuberculous pleurisy. But some of the works from the continents conclude that PADA has poor diagnostic value in tubercular pleural effusion. 3. Van Keimpema A.R. Slaats E.H. Wagenaar J.P. Adenosine deaminase activity, not diagnostic for tuberculous pleurisy. Eur J Respir Dis. 1987; 71: 15-18 PubMed Google Scholar , 4. Maartens G. Bateman E.D. Tuberculous pleural effusions: increased culture yield with bedside innoculation of pleural fluid and poor diagnostic value of adenosine deaminase. Thorax. 1991; 46: 96-99 Crossref PubMed Scopus (86) Google Scholar The methods of adenosine deaminase (ADA) activity estimation are either colorimetry or spectrophotometry, following the enzymesubstrate reaction. It may be one of the reasons why the cut off points for significant ADA activity has been described variously as that of 25 U/L, 2. Piras M.A. Gakis C. Budroni M. Andreoni G. Adenosine deaminase activity in pleural effusions: an aid to differential diagnosis. Br Med J. 1978; ii: 1751-1752 Crossref Scopus (166) Google Scholar 30 U/L, 5. Prasad R. Tripathi R.P. Mukerji P.K. Singh M. Srivastava V.M.L. Adenosine deaminase activity in pleural fluid: a diagnostic test of tuberculous pleural effusion. Indian J Chest Dis Allied Sci. 1992; 34: 123-126 PubMed Google Scholar 45 U/L, 6. Ocana I. Martinez-Vazquez J.M. Segura R.M. Fernandez de Sevilla T. Capdevilla J.A. Adenosine deaminase in pleural fluids: test for diagnosis of tuberculous pleural effusion. Chest. 1983; 84: 51-53 Crossref PubMed Scopus (202) Google Scholar 47 U/L, 1. Valdes L. San Jose E. Alvarez D. Sarandeses A. Pose A. Chomon B. et al. Diagnosis of tuberculous pleurisy using the biologic parameters adenosine deaminase, lysozyme, and interferon gamma. Chest. 1993; 103: 458-465 Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar 50 U/L. 7. Nagraj M.V. Ashokan P.K. Hande H.M. Adenosine deaminase in pleural effusions. J Assoc Physicians India. 1992; 40: 157-159 PubMed Google Scholar Besides the ambiguity of significant PADA level, raised PADA has also been reported in pleural effusions due to rheumatoid arthritis, lymphoma, lung cancer, and mesothelioma, and it has been aptly quoted in a recent editorial. 8. Shah A. Tuberculous pleural effusions: a diagnostic problem [editorial]. Indian J Chest Dis Allied Sci. 1992; 34: 115-116 PubMed Google Scholar Besides the above conditions, increased PADA activity has been recorded in effusions associated with spontaneous pneumothorax and also parapneumonic effusions. 4. Maartens G. Bateman E.D. Tuberculous pleural effusions: increased culture yield with bedside innoculation of pleural fluid and poor diagnostic value of adenosine deaminase. Thorax. 1991; 46: 96-99 Crossref PubMed Scopus (86) Google Scholar All the above facts point to the fact that raised PADA is unlikely to be a useful diagnostic aid (definitely not confirmatory) for tuberculous effusion; however, sufficiently raised PADA may be an aid to differential diagnosis and should be taken into cognizance along with other clinical and laboratory parameters.