Pleural fluid ADA activity in tuberculous pleurisy can be low in elderly, critically ill patients with multi-organ failure.

BACKGROUND: Adenosine deaminase (ADA) activity is typically elevated in patients with tuberculous pleural effusion (TPE), but low ADA has occasionally been reported in patients with TPE. The characteristics of these patients are not well-known, and erroneous exclusion of the possibility of TPE can result in a delayed diagnosis. This study investigated the characteristics of patients with TPE who had low ADA activity. METHODS: We retrospectively reviewed patients with microbiologically or pathologically confirmed TPE between 2012 to 2018 in a tertiary hospital in South Korea. Patients were categorised into two groups: high ADA (≥40 IU/L) and low ADA (< 40 IU/L). Clinical characteristics and Sequential Organ Failure Assessment (SOFA) scores were compared between groups. RESULTS: A total of 192 patients with TPE were included; 36 (18.8%) had ADA < 40 IU/L with a mean ADA activity level of 20.9 (±9.2) IU/L. Patients with low ADA were older (75.3 vs. 62.0 years, p < 0.001) and had a lower mean lymphocyte percentage (47.6% vs. 69.9%, p < 0.001) than patients with high ADA. Patients in the low ADA group had a significantly higher mean SOFA score (2.31 vs. 0.68, p < 0.001), and patients with organ dysfunction were significantly more common in the low ADA group (p < 0.001). Patients with 2 or ≥ 3 organ dysfunctions constituted 19.4 and 13.9% of the patients in the low ADA group, whereas they constituted 7.1 and 1.3% of the patients in the high ADA group (p < 0.001). Multivariate logistic regression analyses showed that older age (odds ratio = 1.030, 95% confidence interval 1.002-1.060, p = 0.038) and a higher SOFA score (odds ratio = 1.598, 95% confidence interval 1.239-2.060, p < 0.001) were significantly associated with low ADA activity in patients with TPE. CONCLUSIONS: ADA activity can be low in patients with TPE who are elderly, critically ill, and exhibit multiorgan failure. Low ADA activity cannot completely exclude the diagnosis of TPE, and physicians should exercise caution when interpreting pleural fluid exams.

Elevated Adenosine Dehydrogenase (ADH) and Positive Tuberculin Test Firstly Misdiagnosed as Tuberculous Pleural Effusion Finally Proved as Pleural Mesothelial Sarcoma by Thoracoscopic Biopsy Pathology: a Case Report and Literature Review.

BACKGROUND: In China, tuberculous pleural effusion is the most common cause for pleural effusion. Elevated ADH and positive tuberculin test usually are characteristic of tuberculous pleural effusion. We reported a 71-year-old male patient with elevated ADH and positive tuberculin test firstly misdiagnosed as tuberculous pleural effusion finally proven as pleural mesothelial sarcoma by thoracoscopic pathology. METHODS: Appropriate laboratory tests and thoracentesis were carried out. Thoracoscopy and pathological biopsy were performed to differentiate tuberculous pleural effusion. RESULTS: Chest CT showed right pleural effusion. ADH in pleural effusion was over 45 U/L and PPD test was positive. No abnormal cells were found in pleural effusion pathology. Pathology of thoracoscopic biopsy proved pleural mesothelioma. CONCLUSIONS: Elevated ADH and positive tuberculin test are not a specific index for tuberculosis and thoracoscopic biopsy pathology is crucial for differential diagnosis.

Thymidine kinase 1 concentration in pleural effusion is a diagnostic marker and survival predictor for malignant pleural effusion.

OBJECTIVE: Thymidine kinase 1 (TK1) is a key enzyme in the pyrimidine salvage pathway. Increased TK1 concentration correlates with cell division. TK1 is an emerging biomarker in cancer diagnosis; however, its effectiveness in diagnosis and management for malignant pleural effusion (MPE) is unclear. We evaluated the diagnostic efficiency and prognostic value of pleural effusion TK1 (pTK1) concentration for MPE. METHODS: From 2013 to 2017, 210 pleural effusion samples were collected from 160 patients diagnosed with MPE and 50 patients diagnosed with benign pleural effusion (BPE). TK1 concentrations in pleural effusion were measured by chemiluminescence dot blot assays. The median follow-up was 12 months. We constructed a receiver-operating characteristic (ROC) curve to find the optimal cutoff value for MPE diagnosis. The hazard ratios were estimated using a multivariable Cox proportional hazard model. A nomogram was drawn to illustrate the prognostic characteristics of MPE. RESULTS: The TK1 concentration in pleural effusion was significantly higher in MPE than BPE (P < 0.001), and patients with MPE could be distinguished by an optimal cutoff value of 3.10 pmol/L with a sensitivity of 0.894 and a specificity of 0.800. The multivariate analysis suggested that pTK1 concentration was an independent predictor of survival in patients with MPE. CONCLUSIONS: The diagnostic and prognostic prediction of MPE may be improved by measuring pTK1 concentration and utilizing a multivariate nomogram.

Diagnostic Value of Vascular Endothelial Growth Factor, Transforming Growth Factor-ß, Interleukin-8, and the Ratio of Lactate Dehydrogenase to Adenosine Deaminase in Pleural Effusion.

PURPOSE: We studied the diagnostic value of cytokines, including vascular endothelial growth factor (VEGF), transforming growth factor-ß (TGF-ß), and interleukin-8 (IL-8), and the ratio of lactate dehydrogenase (LDH) to adenosine deaminase (ADA) in pleural fluid. METHODS: Prospective analysis of 44 inpatients or outpatients with pleural fluid, from December 2016 to March 2017 was conducted. RESULTS: We enrolled patients with malignant pleural effusion (MPE, N = 15), empyema (N = 11), parapneumonic effusion (PPE, N = 7), chronic renal failure (CRF)/chronic heart failure (CHF) (N = 7), and tuberculous pleural effusion (TBPE, N = 4). The pleural fluid values of IL-8 and VEGF were significantly higher in empyema patients than in CRF/CHF or PPE patients. In all patients, the pleural fluid VEGF and IL-8 values were significantly positively correlated (r = 0.405, p = 0.006; r = 0.474, p = 0.047, respectively). TGF-ß was elevated in patients with empyema, PPE, TBPE, and MPE. The pleural LDH-to-ADA ratio in patients with MPE or empyema/PPE was significantly higher than in patients with CRF/CHF or TBPE. LDH and ADA levels correlated significantly only in patients with MPE (r = 0.648, p = 0.009) and empyema/PPE (r = 0.978, p < 0.001). CONCLUSIONS: VEGF and IL-8 production in the pleural cavity appear to accelerate the progression of PPE to empyema, by enhancing vascular permeability associated with inflammation. Sequential sampling would be needed to confirm this. The pleural LDH/ADA ratio may be a useful diagnostic tool for discriminating between various pleural effusion etiologies.

Repeatability of pleural adenosine deaminase measurements in diagnostic evaluation of pleural effusions.

BACKGROUND: A follow-up thoracentesis is proposed in suspected atypical tuberculosis cases. The study aimed to define the variability of pleural ADA values across repeated thoracenteses in different types of pleural effusions (PEs) and to evaluate whether ADA variance, in regard to the cutoff value of 40 U/L, affected final diagnosis. METHODS: A total of 131 patients with PEs of various etiologies underwent three repeated thoracenteses. ADA values were subsequently estimated. RESULTS: 82% and 55% of patients had greater than 10% and 20% deviation from the highest ADA value, respectively. From those patients who had a variance of 20%, 36% had only increasing ADA values, while 19% had only decreasing values. Considering the cutoff value of 40 U/L, only in two cases, ADA decreased below this threshold, which concerned a man with tuberculous pleurisy and a woman with lymphoma both in the course of treatment. Furthermore, only in two cases with rising values, ADA finally exceeded the cutoff limit, which concerned a man with rheumatoid pleurisy and a man with tuberculous pleurisy. Surprisingly, malignant PEs (MPEs) showed a higher percentage of increasing values compared to all other exudates that did not, however, exceed the threshold. CONCLUSION: The determination of pleural ADA levels is a reproducible method for rapid tuberculosis diagnosis. The detected measurement deviations do not appear to affect final diagnosis. In specific situations, repeated ADA measurements may be valuable in directing further diagnostic evaluation. More investigation is needed to elucidate the possible prognostic significance of the increasing trend in ADA values in MPEs.

The pleural fluid lactate dehydrogenase/adenosine deaminase ratio differentiates between tuberculous and parapneumonic pleural effusions.

BACKGROUND: Although pleural fluid lactate dehydrogenase (LDH) and adenosine deaminase (ADA) levels are often used to distinguish between tuberculous pleural effusion (TPE) and parapneumonic pleural effusion (PPE), this can be challenging as the LDH level may vary from normal to severely increased in PPE and a significantly elevated ADA is frequently measured in both conditions. In this study, we evaluated use of the pleural fluid LDH/ADA ratio as a new parameter to discriminate TPE from PPE. METHODS: A retrospective study was conducted in patients with pathologically-confirmed TPE (n = 72) and PPE (n = 47) to compare pleural fluid LDH and ADA levels and LDH/ADA ratios between the 2 groups. A receiver operating characteristic (ROC) curve was constructed for identifying TPE. RESULTS: The median pleural fluid LDH and ADA levels and LDH/ADA ratios in the TPE and PPE groups were: 364.5 U/L vs 4037 U/L (P < .001), 33.5 U/L vs 43.3 U/L (P = .249), and 10.88 vs 66.91 (P < .0001), respectively. An area under the ROC curve of 0.9663 was obtained using the LDH/ADA ratio as the indicator for TPE identification, and the sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were, respectively, 93.62%, 93.06%, 13.48, and 0.068 at a cut-off level of 16.20. CONCLUSIONS: The pleural fluid LDH/ADA ratio, which can be determined from routine biochemical analysis, is highly predictive of TPE at a cut-off level of 16.20. Measurement of this parameter may be helpful for clinicians in distinguishing between TPE and PPE.

Pleural fluid tests to diagnose tuberculous pleuritis.

PURPOSE OF REVIEW: This article summarizes current data regarding the accuracy of pleural fluid tests assisting the diagnosis of tuberculous pleuritis (TBP). RECENT FINDINGS: No pleural fluid test reliably rules-in TBP in settings with low TBP prevalence. Interferon-γ) alone or in combination with adenosine deaminase (ADA) is more reliable than ADA for this purpose in nonlow prevalences. ADA can reliably rule-out TBP in prevalences of less than 40% although in higher prevalences the product of interleukin-27 and ADA is the most accurate rule-out test. SUMMARY: The definite diagnosis of TBP requires the isolation of Mycobacterium tuberculosis from pleural fluid or biopsies. Because of the low sensitivity of pleural fluid cultures and the invasiveness of pleural biopsy techniques, the concept of a pleural fluid test that accurately establishes or excludes TBP diagnosis has been proposed. Numerous pleural fluid tests have been evaluated for this purpose with ADA being the most widely accepted one. During the last years, it has been demonstrated that the ability of ADA to rule-in or rule-out TBP is affected by the prevalence of TBP in the setting where the test is used. The complementary use of interferon-γ or interleukin-27 increases the ability of ADA to rule-in or rule-out the disease, respectively.

Can pleural adenosine deaminase (ADA) levels in pleural tuberculosis predict the presence of pulmonary tuberculosis? A CT analysis.

AIM: To assess the relationship between imaging features of pulmonary tuberculosis at computed tomography (CT) and adenosine deaminase (ADA) values via pleural fluid analysis in patients with pleural tuberculosis. MATERIALS AND METHODS: This retrospective study enrolled 60 patients who underwent fluid analysis for ADA and chest CT and were diagnosed with tuberculosis by culture or polymerase chain reaction of pleural fluid and sputum. The presence of centrilobular nodules, consolidation, cavitation, and mediastinal lymphadenopathy at CT were evaluated. The relationship between ADA values and the pattern of pulmonary involvement of tuberculosis was analysed. RESULTS: Pulmonary involvement was seen in 42 of the 60 patients. A centrilobular nodular pattern was seen in 37 and consolidation in 22. In 17 patients, both findings were identified. A centrilobular nodular pattern was more common than consolidation or cavitary lesions. When ADA values were high, pulmonary involvement was more frequent (p=0.002). Comparing low and high ADA groups using an obtained cut-off value of 80 IU/l, the high group had more frequent pulmonary involvement (p<0.001). CONCLUSION: Patients with tuberculous pleurisy who had high ADA values had a higher probability of manifesting pulmonary tuberculosis. High ADA values may help predict contagious pleuroparenchymal tuberculosis. The most common pulmonary involvement of tuberculous pleurisy showed a centrilobular nodular pattern.

Radiologic and laboratory differences in patients with tuberculous and parapneumonic pleural effusions showing non-lymphocytic predominance and high adenosine deaminase levels.

PURPOSE: Tuberculous pleural effusion (TPE) is characterized by lymphocytic predominance and high adenosine deaminase (ADA) levels. However, TPEs sometimes present non-lymphocytic predominance, and parapneumonic effusion (PPE) often exceeds the cutoff value of ADA for TPE. Thus, the differential diagnosis of cases with pleural fluid (PF) showing non-lymphocytic predominance and high ADA levels is challenging. However, limited data concerning the clinical differences in these patients are available. METHODS: A retrospective study was conducted on TPE and PPE patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L in 2009-2013 in a South Korean tertiary referral hospital. The clinical, laboratory, and computed tomography (CT) findings between the groups were analyzed using multivariate logistic regression to develop a prediction model with independent factors for TPE. RESULTS: Among 353 patients with TPE, 24 (6.8 %) showed PF with non-lymphocytic predominance and ADA levels of ≥40 U/L. Twenty-eight PPE patients who presented PF findings comparable with those of TPE patients were included in the control group. In the final analysis, PF ADA levels >58 U/L and nodular lung lesions on CT were independent positive predictors, while loculated effusion was an independent negative predictor for TPE. Using the prediction model, a score ≥ +3 provided a sensitivity of 88 %, specificity of 93 %, positive predictive value of 91 %, and negative predictive value of 90 % for TPE. CONCLUSION: PF ADA levels, nodular lung lesions, and loculated pleural effusion may help differentiate TPE from PPE in patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L.

Comparative Study of Adenosine Deaminase and Other Conventional Diagnostic Parameters in Diagnosis of Tuberculous Pleural Effusion.

Though pulmonary tuberculosis is the common presentation of Mycobacterium tuberculosis infection, extra-pulmonary tuberculosis is also a growing problem worldwide. Tuberculous pleural effusion is the second frequent form of extra-pulmonary presentation after tuberculous lymphadenitis and if untreated up to 65% of patients with tubercular pleural effusions will eventually develop active TB. Traditional diagnostic methods are very useful for the diagnosis of pulmonary TB but have a low yield when applied to pleural fluid. So,the aim of this study was to evaluate the diagnostic value of ADA level in plural fluid and other conventional methods for diagnosis of tubercular plural effusion. This was a cross sectional study. This study was carried out in 64 Patients suffering from plural effusion and were consecutively selected and divided into two groups: tuberculous (n=40) and non tuberculous (n=24), depending upon etiology. Details clinical history, physical examination, routine and other relevant investigations including ADA estimation was measured. The mean value of ADA in the tuberculous group was 64.11 ± 19.50 U/L which was significantly higher (p<0.05). Cut off value of ADA was ≥ 40 U/L with 97% sensitivity and 93%specificity. In this study, sensitivity, specificity, PPV and NPV of ADA level in pleural effusion were more significant than other conventional parameters.

Role of adenosine deaminase in diagnosis of tubercular pleural effusion.

The diagnosis of pleural tuberculosis (TB) continues to be a challenge in clinical practice. Traditional diagnostic methods are very useful for the diagnosis of pulmonary TB but have a low yield when applied to pleural fluid. It is produced during the inflammatory process triggered by the M. tuberculosis. Usefulness of adenosine deaminase (ADA) estimation in pleural fluid has been shown as a reliable chemical bio-marker specially when there is suspicion of tuberculosis in endemic areas. ADA level was determined in the pleural fluid of 100 patients present with pleural effusion admitted at Mymensingh Medical College Hospital during the period of March 2012 to September 2012. ADA level was >40IU/L among the 52 tubercular pleural effusion patients with sensitivity & specificity is 100% and 66% respectively. Thus is evident that ADA level can be used along with conventional methods for diagnosis of pleural TB.

Factors affecting pleural fluid adenosine deaminase level and the implication on the diagnosis of tuberculous pleural effusion: a retrospective cohort study.

BACKGROUND: Adenosine deaminase (ADA) is useful in the diagnosis of tuberculous pleural effusion (TPE). This study aims to determine the factors affecting pleural fluid ADA levels and to establish the optimal ADA levels for diagnosis of TPE for different age groups. METHODS: This was a retrospective study from January 2007 to October 2011. One hundred and sixty patients who had pleural fluid ADA performed for investigation of pleural effusion were analyzed. Variables examined included demographics, pleural fluid characteristics and peripheral blood counts. The ADA cut-offs according to age were selected using the receiver operating characteristic (ROC) curve. RESULTS: The mean pleural fluid ADA was significantly higher in the TPE group (100 ± 35 IU/L) compared to non TPE patients (30 ± 37 IU/L). There was significant correlation between pleural fluid ADA and age, pleural fluid protein, LDH, and fluid absolute lymphocyte count. The strongest correlation was seen with age (r = -0.621). For patients ≤ 55 years old the ROC for ADA had area under curve (AUC) of 0.887. A pleural fluid ADA of 72 IU/L had sensitivity of 95.1%, specificity of 87.5%, positive predictive value (PPV) of 95.1% and negative predictive value (NPV) of 87.5% for the diagnosis of TPE. For patients > 55 years old the AUC is 0.959. ADA of 26 IU/L had a sensitivity of 94.7%, specificity of 80.4%, PPV of 62% and NPV of 97.8%. CONCLUSIONS: There is a significant negative correlation between pleural fluid ADA and age. For older patients, a lower ADA cut-off should be used to exclude TPE.

[Case of tuberculous pleurisy distinguished from pleurisy caused by Mycoplasma infection].

We report a case of tuberculous pleurisy that required differentiation from pleurisy caused by Mycoplasma infection. A 28-year-old woman presented to a clinic with fever and pain on the left side of her chest. A chest radiograph revealed pleural effusion in the left thorax, and the condition was diagnosed as bacterial pleurisy. The patient was referred to our hospital because of an increase in the pleural effusion despite antibiotic treatment. Mycoplasma infection was suspected because the patient was young, the white blood cell count was not elevated, and the result of the ImmunoCard Mycoplasma test (IC) for Mycoplasma pneumoniae-specific IgM antibodies was positive. However, the fever persisted even after treatment with azithromycin and pazufloxacin. The left pleural effusion was exudative, with lymphocytosis and high adenosine deaminase (ADA) levels. The results of the QuantiFERON test were positive. Therefore, tuberculous pleurisy was diagnosed, and the effusion subsided after treatment with standard anti-tuberculosis chemotherapy. Although detection of Mycoplasma infection using the IC is rapid and simple, the accuracy of this test is poor. The patient was first diagnosed with pleurisy of Mycoplasma origin because of a single high-particle agglutination titer of 1: 320 and because of the presence of exudative pleural effusion with lymphocytosis and elevated ADA levels, which has been reported in patients with Mycoplasma infection. The results of the IC test and the ADA level of the pleural effusion might not be reliable when distinguishing between tuberculous pleurisy and pleurisy caused by Mycoplasma infection.

When pleural potassium exceeds 5.0 mEq/L, high pleural adenosine deaminase levels do not necessarily indicate tuberculous pleuritis.

BACKGROUND AND OBJECTIVE: The aim of this study was to determine whether high levels of pleural adenosine deaminase (pADA) are predictive for tuberculosis when pleural effusions do not satisfy the criteria for lymphocytic effusions or show neutrophil predominance. METHODS: This was a retrospective observational study of 147 consecutive patients with exudative pleural effusions that were diagnosed by analysis of fluid samples during a 3-year period from 1 April 2007 to 31 March 2010. Multiple linear correlation tests were used to assess clinical variables as possible predictors of high pADA levels. RESULTS: High pleural LDH (pLDH) and pleural potassium (pK) levels were associated with high pADA levels (P < 0.0001). Although there was a linear correlation between pLDH and pADA levels in patients with parapneumonic effusions (PPE) (n = 75), tubercular effusions (n = 21), malignant effusions (n = 41) and miscellaneous effusions (n = 10), a significant linear correlation between pK and pADA levels was observed only in patients with PPE (ρ = 0.525, P < 0.0001). When the cut-off value for pK was set at 5.0 mEq/L, pADA levels were >50 IU/L and pK levels were >5.0 mEq/L in only one patient (5%) in the tuberculosis group (n = 21) and 15 patients (12%, all with PPE) in the non-tuberculosis group (n = 126). CONCLUSIONS: When pK levels exceed 5.0 mEq/L, high pADA levels do not necessarily indicate the presence of tuberculous pleuritis.

[Application of combined telomerase activity analysis and immunocytochemistry in cytopathologic diagnosis].

OBJECTIVE: To evaluate the application of traditional cytomorphology, telomerase activity analysis and immunocytochemistry in cytopathologic diagnosis of pleural effusion and bronchoalveolar lavage samples. METHODS: A total of 123 agar-paraffin double-embedded pleural effusion and bronchoalveolar lavage fluid samples were enrolled into study. The cytomorphologic features were reviewed and correlated with immunocytochemical findings and telomerase activity. RESULTS: Telomerase activity was detected in 53 specimens using the real-time telomeric repeat amplification protocol. Amongst the cases studied, 39 samples (31.7%) contained overtly malignant cells while 20 cases (16.0%) were equivocal by conventional cytology. After verification by immunocytochemistry and clinical follow-up data, the diagnostic accuracy of telomerase activity and cytology was 87.0% and 82.1%, respectively. The sensitivity (97.6%) and specificity (100.0%) of cytology examination, when combined with telomerase activity analysis, were greater than those of cytology examination or telomerase activity analysis alone. CONCLUSIONS: Telomerase activity analysis can be used as an adjunctive investigative tool in cytology assessment of pleural effusion and bronchoalveolar lavage samples. The diagnostic accuracy can be further improved with the application of immunocytochemistry on agar-paraffin double-embedded cell block tissues.

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.

[A case of primary effusion lymphoma with elevation of ADA activity in pleural effusion].

A 74-year-old man was referred to our hospital with complaint of dyspnea and left pleural effusion. The pleural effusion was exudative and lymphocytic with elevation of adenosine deaminase (ADA). Antitubercular agents were administered on a diagnosis of tuberculous pleuritis, but the pleural effusion did not improve. After he had been followed up with diuretic agents during about 2 years, he suffered cardiac tamponade and right pleural effusion. We diagnosed primary effusion lymphoma based on the cytology findings of the pleural effusion. The measurement of ADA activity in pleural effusions was useful for diagnosis of tuberculous pleuritis, but not only tuberuculous pleuritis but also lymphoma or other diseases can show elevation of ADA activity in pleural effusions.

Diagnostic tests for tuberculous pleural effusion.

The investigation of pleural effusion has been greatly assisted by advancements in pleural fluid analysis. In the case of tuberculous pleural effusion, diagnosis traditionally requires the demonstration of acid fast bacilli in the pleural space using microbiological or histological techniques. In recent years, there has been progress in pleural fluid analysis in suspected tuberculous effusions, with particular interest in adenosine deaminase and interferon-γ. These individual tests are quite sensitive and specific; however, data are sparse on the benefits that multiple-parameter testing may have when analysed in combination. We reviewed the literature to investigate the evidence for multiple-parameter testing, both biochemical and clinical, in the evaluation of tuberculous effusion.

The utility of pleural amylase measurement in metastatic mucinous adenocarcinoma.

We describe a case of exudative pleural effusion in a patient with mucinous pulmonary adenocarcinoma. Pleural fluid examination showed markedly raised amylase with normal serum amylase concentration. There was no clinical or radiological evidence of oesophageal rupture or pancreatitis. The case illustrates the importance of considering pulmonary malignancy in the context of amylase-rich pleural effusion. Causes of amylase-rich pleural effusion and the significance of isoenzyme analysis are discussed.

[Evaluation of the diagnostic value of adenosine deaminase activity in tuberculous pleuritis].

OBJECTIVE: To investigate the clinical value of pleural fluid adenosine deaminase (ADA) activity in differentiating tuberculous pleural effusions (TPE) from malignant effusions. METHODS: The serum and pleural adenosine deaminase activity of 91 cases confirmed by pleural biopsy through medical thoracoscopy were retrospectively analyzed. TPE was confirmed in 49 cases and malignant effusion in 42 cases. The optimal cutoff for TPE was determined by using the ROC curve. RESULTS: The mean pleural ADA was significantly (t = 7.383, P < 0.01) higher in PTE (46 +/- 26) U/L as compared to malignancy (16 +/- 8) U/L, so was the pleural fluid/serum ADA ratio (4.1 +/- 4.0 vs 1.76 +/- 1.2, t = 3.852, P < 0.01), but there was no statistically significant difference between malignant and tuberculous effusion in serum ADA activity [(13 +/- 5) U/L vs (12 +/- 6) U/L, t = 1.582, P > 0.05]. The cutoff value of pleural ADA for PTE was 28.7 U/L, with a sensitivity of 75.5% and a specificity of 95.2%. CONCLUSIONS: Pleural fluid, but not serum, ADA activity, can be used for the differentiation between tuberculous and malignant pleural effusions.