Vascular endothelial growth factor in pleural effusions of different origin.

This study aimed to determine the diagnostic relevance of vascular endothelial growth factor (VEGF) in the pleural fluid and serum of patients with pleural effusions of different aetiology. VEGF was quantified in the pleural effusion fluid and serum of 96 patients with malignancies (58 lung cancers (CA) and 38 tumours with secondaries to the lung (TM)), 45 with congestive heart failure (CHF), 28 with tuberculosis (TB), 45 with acute infections (INF), and in the serum of 20 healthy controls. VEGF pleural effusion concentrations were significantly different in the main diagnostic groups. VEGF was higher in effusions of patients with malignancies (CA as well as TM) in comparison with INF, TB or CHF. In serum, however, high VEGF concentrations indicated CA, TM or INF, but not TB or CHF. Despite significant differences of VEGF levels in different patient groups, receiver-operating characteristic analysis revealed insufficient diagnostic value of VEGF for differential diagnosis of pleural effusions. In conclusion, vascular endothelial growth factor serum concentration is highly suggestive of the presence of lung disease in general, except for tuberculosis. In effusion fluid, the presence of vascular endothelial growth factor clearly indicates inflammatory or malignant origin. However, for diagnostic use, additional parameters besides vascular endothelial growth factor are mandatory.     

Exudative effusions in congestive heart failure

OBJECTIVES: Pleural effusions due to congestive heart failure (CHF) typically are transudates, but an occasional patient with CHF is found to have an exudate in the absence of an apparent cause other than CHF. We sought to determine the incidence and clinical significance of such exudative effusions. DESIGN: Patients with CHF and effusions seen during the 7-year period from January 1994 through December 2000 were identified from their hospital discharge diagnoses and radiographs, while those who had undergone thoracentesis were identified from a review of the laboratory logs. The presenting symptoms and clinical course were determined from a review of the medical records. The effect of RBC contamination on pleural fluid lactate dehydrogenase (LDH) levels was determined by measuring the LDH activity of mock pleural fluid containing known amounts of RBC. RESULTS: Seven hundred seventy patients had CHF with an effusion, but only 175 patients underwent a thoracentesis. In this select group, 86 patients had transudates and 89 had exudates. A noncardiac cause for the exudate was readily identified in 59 patients by hospital discharge, and 7 more patients had an etiology found during follow-up. Eleven of the remaining 23 patients had undergone coronary artery bypass graft (CABG) surgery > or = 1 year prior to presentation, and 50% of the effusions in patients who had undergone CABG surgery were exudates. Thus, CHF-related exudates were identified in only 12 patients, and in 4 of these patients the exudates could be explained by RBC contamination of the pleural fluid. The clinical presentation of patients with CHF-associated exudates was similar to that of CHF patients with transudates. CONCLUSION: In most patients who have CHF and an exudative effusion, there is a noncardiac cause for the pleural effusion. The high frequency of exudates in patients with a history of CABG indicates a persistent impairment in lymphatic clearance from the pleural cavity. Exudative effusions due solely to CHF are rare.     

Diagnostic value of pleural fluid N-terminal pro-brain natriuretic peptide levels in patients with cardiovascular diseases

Background and objective:   The diagnosis of the cause of pleural effusions caused by cardiovascular diseases such as congestive heart failure (CHF) and acute pulmonary embolism is sometimes difficult. The purpose of the present study was to evaluate the utility of pleural fluid levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) in differentiating pleural effusions due to CHF, pulmonary embolism and post-coronary artery bypass graft (CABG) surgery.
Methods:   The levels of pleural fluid NT-proBNP were measured by ELISA in a total of 40 patients: 10 with CHF, 10 with pulmonary embolism, 10 post-CABG and 10 with carcinoma.
Results:   The median level of NT-proBNP in the pleural fluid of patients with CHF was 5390 pg/mL (25th to 75th percentiles, 4566 to 8158 pg/mL), which was significantly higher than that in patients with post-CABG effusions (424 pg/mL, 352 to 873), with pulmonary embolism (311 pg/mL, 212 to 1159), or with carcinoma (302 pg/mL, 208 to 626) ( P  < 0.001, CHF group vs all other groups). In receiver-operating curve analysis, an NT-proBNP level of ≥2220 pg/mL demonstrated a sensitivity of 100% and a specificity of 96.7% for the identification of CHF.
Conclusions:   Measurement of the NT-proBNP level in pleural fluid is accurate in diagnosing the etiology of the effusion as CHF. Pleural fluid levels above 2220 pg/mL are essentially diagnostic that the pleural effusion is due to CHF.     

Serum and pleural fluid N-Terminal-Pro-B-Type natriuretic peptide concentrations in the differential diagnosis of pleural effusions

Currently, new biomarkers like N-Terminal-Pro-B-Type natriuretic peptide (NT-proBNP) have been used in the differential diagnosis of pleural effusions. In our study, we aimed to investigate the diagnostic value of NT-proBNP, especially in cardiac originated pleural effusions. Forty-five patients with pleural effusions were included in the study. NT-proBNP levels and biochemical markers involved in the Light's criteria were analyzed in pleural fluid and serums of the patients. Pleural fluid culture, AFB smear, cytology were performed where they were indicated according to the clinical evaluation. In patients, to whom cardiac pathology was considered to be; cardiological evaluation and echocardiography were also done. Thirty-eight pleural effusions were exudative and, 7 were transudative according to the Light's criteria. Final diagnosis were malignant effusion in 13, infection (tuberculosis/pneumonia) in 10, congestive heart failure in 21, and other conditions related with pleural effusion in 1 of the patients. Median (25th to 75th percentiles) NT-proBNP levels of serum and pleural fluid due to congestive heart failure (CHF) were 4747 pg/mL (931-15754) and 4827 pg/mL (1290-12.430) while median NT-proBNP levels of serum and pleural fluid related with non-cardiac reasons were 183 pg/mL (138-444) and 245 pg/mL (187-556) respectively. NT-proBNP levels of serum and pleural fluid were significantly high in CHF (p< 0.001 for both). When four groups were compared serum and pleural fluid NT-proBNP levels were highest in the CHF group which was followed by malignancy, infection and others (p< 0.001 for both). Fourteen of 21 patients who were accepted to have congestive heart failure as the final diagnosis by a cardiological evaluation had an exudative pleural fluid according to the Light's criteria. Serum and pleural fluid NT-proBNP levels were higher in transudates and this reached statistically significance for pleural fluid (p= 0.009). We suggest that measurement of pleural fluid NT-proBNP is a smart approach and pleural fluid NT-proBNP can reflect cardiac origin of effusions better than serum NT-proBNP and Light's criteria.     

Antinuclear antibody testing in pleural fluid for the diagnosis of lupus pleuritis

We sought to determine whether measuring antinuclear antibodies (ANA) and their specificities [dsDNA, extractable nuclear antigens (ENA)] on pleural fluid may contribute to the differential diagnosis of pleural effusions. ANA were tested by indirect immunofluorescence on Hep-2 cells in the pleural fluid of 266 patients with effusions of different etiologies, including 15 lupus pleuritis. The cutoff value for diagnostic use was set at 1:160. Pleural fluid analysis of specific autoantibodies, such as anti-dsDNA and anti-ENA, was also performed if a positive ANA test was obtained. All patients with lupus pleurisy and 16 of 251 (6.4%) patients with pleural effusions secondary to other causes were ANA positive. Fifty-six percent of the positive ANAs in non-lupus pleural fluids were due to neoplasms. The pleural fluid ANA titers were low (< or = 1:80) or absent in two patients with systemic lupus erythematosus (SLE) and effusions due to other factors. Whereas ANA staining patterns in pleural fluid did not help to discriminate lupus pleuritis from non-lupus etiologies, the absence of pleural fluid anti-dsDNA or anti-ENA favored the latter. ANAs in pleural fluid provided no additional diagnostic information beyond that obtained by the measurement in serum and, therefore, these tests need not be routinely performed on pleural fluid samples. However, in patients with SLE and a pleural effusion of uncertain etiology, lack of ANAs or specific autoantibodies in pleural fluid argues against the diagnosis of lupus pleuritis.     

High diagnostic accuracy of NT-proBNP for cardiac origin of pleural effusions.

A prospective study was performed to evaluate the diagnostic accuracy of N-terminal-pro-B-type natriuretic peptide (NT-proBNP) levels, measured simultaneously in serum and pleural fluid, in identifying pleural effusions due to heart failure. Pleural fluid and serum samples from all patients presenting for thoracentesis between April 2004 and May 2005 were simultaneously collected. The discriminative properties of NT-proBNP levels in identifying pleural effusions due to heart failure were determined by receiver operating characteristic curve analysis and compared to the diagnostic value of finding a transudate by Light's criteria. Ninety-three patients were evaluated, 27% with cardiac effusion and 73% with exudative effusions of various cause. Levels of NT-proBNP in pleural fluid and serum correlated closely. Serum and pleural fluid NT-proBNP levels were significantly elevated in patients with cardiac effusion. With a cut-off value of 4,000 ng.L(-1), NT-proBNP levels in pleural fluid and serum displayed comparably high diagnostic accuracies of 92 and 91%, respectively. All patients misclassified by Light's criteria were correctly identified by measuring NT-proBNP levels. N-terminal-pro-B-type natriuretic peptide levels in either pleural fluid or serum showed a high diagnostic accuracy compared to traditional criteria. Thus measuring N-terminal-pro-B-type natriuretic peptide is a valuable additional diagnostic tool for the detection or exclusion of cardiac origin of pleural effusions.     

胸腔积液端粒酶和癌胚抗原测定对良恶性胸腔积液诊断价值对比研究

目的 研究胸腔积液端粒酶活性在良恶性胸腔积液中的鉴别诊断价值,并与癌胚抗原（CEA）进行比较。方法 用聚合酶链反应－酶联免疫吸附分析法（PCR－ELISA）检测胸腔积液端粒酶活性,用酶免疫分析法（EIA）检测胸腔积液CEA水平。根据最终诊断结果,65例患者分成2组：（1）非恶性胸腔积液组：35例,（2）恶性胸腔积液组：30例。并将端粒酶活性检测结果与胸腔积液CEA测定结果进行比较。结果 非恶性胸腔积液中端粒酶阳性2例（5．7％）,恶性胸腔积液中阳性27例（90％）,端粒酶活性测定诊断恶性胸腔积液的灵敏度为0．90,特异度0．94,阳性预测值0．93,阴性预测值0．92,正确率0．92。CEA诊断灵敏度为0．60,特异度0．89,阳性预测值0．82。阴性预测值0．72,正确 率0．75。结论 胸腔积液端粒酶活性鉴别良恶性胸腔积液的诊断效能明显优于CEA测定,可作为一种诊断恶性胸腔积液的辅助手段。     

The diagnostic values of serum, pleural fluid and urine neopterin measurements in tuberculous pleurisy.

SETTING: Pulmonary department of a medical academy in Ankara, Turkey. OBJECTIVE: Neopterin is a marker of cell-mediated immunity, and it has been demonstrated that neopterin levels of various body fluids could be elevated in tuberculosis. We aimed to investigate diagnostic values of serum, pleural fluid and urine neopterin measurements in tuberculous pleurisy (TP). DESIGN: Serum, pleural fluid and urine neopterin levels were measured in 34 patients with TP and in 29 patients with pleural effusion of non-tuberculous origin as controls. RESULTS: Neopterin levels in serum, pleural fluid and urine (38.28 +/- 14.18 nmol/l, 38.97 +/- 14.18 nmol/l and 759.15 +/- 622.74 micromol/mol, respectively) were significantly higher in patients with TP than those with non-tuberculous pleural effusion (22.57 +/- 6.02 nmol/l, 21.88 +/- 6.90 nmol/l and 343.10 +/- 233.65 micromol/mol, respectively). Pleural fluid neopterin > or =30 mol/l gave the best diagnostic yield, with 85% sensitivity, 93% specificity, 94% positive predictive value, 84% negative predictive value and 89% diagnostic accuracy, although it is not superior to pleural fluid adenosine deaminase determination. CONCLUSION: We have suggested that elevated serum, pleural fluid and urinary neopterin levels in TP with respect to pleural effusions of non-tuberculous origin may reflect activation of cell-mediated immunity and that pleural fluid neopterin measurement may be of value in the differential diagnosis of TP.     

Limited additive value of pleural fluid carcinoembryonic antigen level in malignant pleural effusion

OBJECTIVE: To assess the additive value of pleural fluid carcinoembryonic antigen (CEA.PF) level in the diagnosis of malignant pleural effusion. METHODS: Thoracentesis and closed pleural biopsy were performed in consecutive patients with pleural effusions. CEA.PF, cell analysis, and biochemical, cytopathologic and microbiologic studies were carried out. Further diagnostic interventions were undertaken if initial tests were inconclusive. RESULTS: A total of 176 patients were evaluated. The effusions proved malignant in 78 patients (44%). Benign etiologies were diagnosed in 89 cases, comprising 51 tuberculous pleurisies, 12 empyemas, 26 others. The cause was unknown in 9 patients. Median (range) in ng/ml of CEA.PF were 233 (1-12,500) in malignant vs. 2.5 (0.3-9) in tuberculosis, 1.4 (0.1-2) in transudates, 19.4 (0.6-312) in empyemas, p < 0.001. Receiver operating characteristic curve identified 10 ng/ml as the best cut-off for CEA.PF, yielding a sensitivity of 0.77, a specificity of 0.94, a positive and negative predictive value of 0.92 and 0.82, respectively. Among the 78 patients with malignant effusions, CEA.PF was elevated but initial cytopathologic study was nondiagnostic in 14 patients (18%). Prompted by the raised CEA.PF, further diagnostic interventions were undertaken and secured the diagnosis of malignancy in all of these 14 patients. CONCLUSIONS: CEA.PF level adds limited value on cytopathologic study in the diagnosis of malignant pleural effusions. It potentially identifies 18% of patients with malignant effusions who require further investigations despite negative initial cytopathologic study.     

Diagnostic significance of gamma-interferon in tuberculous pleurisy

We studied ADA and gamma interferon (gamma-IFN) levels in pleural fluid of 45 cases presenting with pleural effusion to the Ankara University School of Medicine Chest Diseases Hospital between September 2001 and September 2002. Fifteen patients had TB pleurisy, 20 patients had malignant pleurisy and 10 patients had transudative pleural effusion. The cut-off value for pleural fluid gamma-IFN levels were 12 pg/mL. According to this, all patients with transudative effusions, 19 of 10 patients with malignant effusions and 2 of 15 patients with tuberculous (TB) effusions had pleural fluid gamma-IFN levels under the cut-off value. In exudative effusions, sensitivity and specificity of gamma-IFN were 87% and 95% respectively. The sensitivity of pleural fluid ADA levels was 86% and specificity of pleural fluid ADA levels was 100%. Pleural fluid ADA levels in TB effusions were significantly higher than the non-TB effusions. Also there were no statistically significant differences between pleural fluid ADA and g-IFN levels according to sensitivity and specificity. As a result, we have shown that gamma-IFN is a valuable test in diagnosis of TB pleurisy. We think that when it is used routinely, it will be a good alternative to the conventional invasive diagnostic tests.     

Effects of Coexisting Pneumonia and End-stage Renal Disease on Pleural Fluid Analysis in Patients With Hydrostatic Pleural Effusion

BackgroundIn individual patients, especially those who are hospitalized, several conditions often coexist that may be responsible for the development of a pleural effusion and may affect the pleural fluid analysis (PFA). The objective of this study was to investigate the effects of end-stage renal disease and pneumonia on PFA in patients with hydrostatic pleural effusion.MethodsIn a retrospective analysis of 1,064 consecutive patients who underwent thoracentesis at a university hospital, cell counts and pleural fluid protein, lactate dehydrogenase, pH, and glucose levels were examined in those (n = 300) with clinical evidence of hydrostatic pleural effusion.ResultsThe 300 patients (28.1%) with pleural effusions had congestive heart failure (CHF), circulatory overload (CO), or both. Expert consensus was achieved in 66 (22%) for CHF as the sole diagnosis (SCHF), 30 (10%) for CHF and coexisting pneumonia (PCHF), and 26 (8.7%) for end-stage renal disease (ESRD) with coexisting CO or CHF. The remaining 178 patients were excluded because of complicating conditions. There were minor, but statistically significant differences in pleural fluid/serum protein ratios in patients with ESRD with coexisting CO or CHF compared with SCHF. Compared with SCHF, there were statistically significant tendencies for higher protein and lactate dehydrogenase concentrations and lower pH levels in those with PCHF. The total nucleated cell count and the absolute neutrophil count were significantly higher in PCHF.ConclusionsESRD in patients with hydrostatic pleural effusions has a minimal effect on the PFA. Coexisting pneumonia most often results in an exudative effusion in patients with CHF.     

NT-brain natriuretic peptide levels in pleural fluid distinguish between pleural transudates and exudates

BACKGROUND: Pleural effusion is not pathognomic and distinguishing between transudates and exudates often presents a diagnostic dilemma. The purpose of our study was to examine whether the inclusion of pleural fluid brain natriuretic peptide (BNP) measurement into the analysis improves the diagnostic accuracy of pleural effusion. METHODS: The pleural effusion of 14 patients with CHF (group A) and 14 subjects with different pleural pathology (group B) were analyzed. Samples of pleural fluid and serum were obtained from all patients on admission and biochemical analysis, bacterial and fungal culture, acid-fast bacilli smear and culture and cytology were performed on the pleural fluid. In vitro quantitative determination of N-terminal pro-Brain natriuretic peptide (NT-proBNP) in serum and pleural fluid were performed by electrochemiluminescence immunoassay proBNP method on an Elecsys 2010 (Roche) analyzer. RESULTS: The median NT-proBNP levels in groups A and B were 6295 pg/ml and 276 pg/ml, respectively: (P=0.0001). There was no overlap between the two groups. While the Light's criteria had a sensitivity of 93% and specificity of 43% for transudates, the pleural fluid NT-proBNP level accurately differentiated between the two groups. CONCLUSIONS: The pleural NT-proBNP levels were elevated in all patients who had transudate. Therefore if the NT-proBNP levels of pleural effusion are within the normal range, transudate resulting from congestive heart failure can be ruled out. Our results suggest that the inclusion of pleural fluid NT-proBNP measurement in the routine diagnostic panel would enhance discrimination among the different causes of pleural effusions.     

Diagnostic value of interleukin-1alpha, interleukin-6, and tumor necrosis factor in pleural effusions

STUDY OBJECTIVES: Interleukin (IL)-1alpha, IL-6, and tumor necrosis factor (TNF)-alpha were measured in pleural fluid from 57 patients with pleural effusion in order to evaluate the diagnostic utility of these cytokines. We studied 20 patients with malignant pleural effusion, 11 patients with parapneumonic pleural effusion, 9 patients with tuberculous pleural effusion, and 17 patients with transudative pleural effusion. Cytokines were measured by radioimmunoassay. SETTING: University tertiary hospital. RESULTS: The mean values of the three cytokines measured in pleural fluid or in serum were significantly higher in patients with exudates than with transudates (p < 0.05). The ratio of IL-6 in pleural fluid to serum was significantly higher in exudates than in transudates (p < 0.05). The level of IL-6 in pleural fluid was significantly higher in tuberculous than malignant (p < 0.007) or parapneumonic pleural effusions (p < 0.04). No significant difference between the three types of exudates was found in pleural fluid levels of IL-1alpha or TNF-alpha. CONCLUSIONS: Serum levels of IL-1alpha, TNF-alpha, and in particular IL-6 can distinguish exudates from transudates, while pleural fluid IL-6 levels could be useful as an additional marker in the differential diagnosis of tuberculous, malignant, and parapneumonic exudates. Finally, our results suggest that there is local cytokine production in exudative pleural effusions.     

Alkaline phosphatase in pleural effusions

BACKGROUND: Pleural effusion (PF) is a common clinical presentation in several diseases. Various parameters from pleural fluid have been studied to identify the cause. The diagnostic value of these parameters varies. The present study was carried out to evaluate the value of alkaline phosphatase concentration in the pleural effusions as a diagnostic tool. METHODS: One hundred and one patients with pleural effusion admitted over a period of two years were studied. The diagnosis was confirmed by pleural biopsy and cytology for malignant cells. RESULTS: Pleural fluid alkaline phosphatase levels of more than 75 mg/dl was found in exudative effusions and less than 75 mg/dl in transudative ones. But it did not differentiate tubercular pleural effusions from other exudative ones. CONCLUSION: Pleural fluid alkaline phosphatase of >75 mg/dl is a useful biochemical marker to suggest exudative effusions.     

Lymphocyte subpopulations analysis in pleural fluid and peripheral blood in patients with lymphocytic pleural effusions.

Lymphocyte subpopulations analysis by an 11-monoclonal antibody (MoAb) panel was carried out in pleural fluid and in peripheral blood in 30 patients affected by newly diagnosed, untreated pleural effusion of different etiology determinated with bacteriological, cytological or histological criteria. Lymphocytes were the predominant cell type, in pleural fluid, in neoplastic pleural effusions as well as in congestive heart failure pleural effusions and, especially, in tuberculous pleural effusions. Lymphocyte analysis in pleural fluid and in peripheral blood suggests the involvement of different mechanisms for the lymphocyte accumulation in the pleural space according to different etiologies. Tuberculous pleural effusions showed an evident CD4+ and TEC T5.9+ lymphocyte accumulation from peripheral blood. In these patients, cutaneous skin test response to purified protein derivative was strongly related to this situation. In neoplastic pleural effusions there was a lower percentage of CD4+ lymphocytes, reflecting circulating lymphocyte pool; however, in neoplastic pleural effusions, various lymphocyte patterns may be sometimes observed depending on different histologies. Passive lymphocyte accumulation seems to be the most important mechanism in congestive-heart-failure pleural effusions.     

Meaning and diagnostic value of determining the lysozyme level of pleural fluid

We determined the levels of lysozyme in pleural fluid and serum in 141 patients with the following different causes for their pleural effusions: tuberculosis; neoplasias; transudates; parapneumonic, not complicated; empyemas; and miscellaneous. The lysozyme level of the pleural fluid and the ratio of that level over the serum level of lysozyme (PL/SL ratio) was meaningfully increased in patients with empyema (p less than 0.01). The groups with tuberculous and neoplastic effusions showed significant differences in the PL/SL ratio (p less than 0.01). The existence of a raised PL/SL ratio suggested important local synthesis of lysozyme, and it came up in empyemas and tuberculosis, unlike the other groups. Excluding the patients with empyemas, a PL/SL ratio of 1.2 showed a sensitivity of 100 percent, specificity of 94.9 percent, positive predictive value of 94.7 percent, negative predictive value of 100 percent, and accuracy of 97.3 percent for the diagnosis of tuberculous pleural effusion. All of this suggests that the determination of the lysozyme level can be an easy method of great usefulness in the initial diagnosis of pleural effusions.     

Use of pleural fluid C-reactive protein in diagnosis of pleural effusions

The aims of the study were to assess whether C-reactive protein (CRP) is a sensitive marker for discriminating between transudative and exudative and pleural effusions to evaluate whether it can be used to distinguish inflammatory pleural effusions from other types of effusion. Pleural fluid and serum CRP levels were obtained in 97 patients with pleural effusion, using an immunoturbidimetric method (Olympus AU-600 autoanalyser). We compared CRP levels between transudates and exudates, inflammatory effusions and other types of effusion. According to the criteria used, 16 patients were included in the transudate group and 81 patients in the exudate group. Pleural fluid CRP levels were significantly lower in the transudate group (P<0.04; 14.9 +/- 4.9 mg l(-1) and 35.5 +/- 4.9 mg l(-1) respectively). Also, the ratio of pleural fluid to serum was significantly lower in the transudate group (P<0.009; 0.8 +/- 0.5 mg l(-1) and 2.8 +/- 0.7 mg l(-1), respectively). In the exudate group, 35 patients had neoplastic effusions, 10 chronic non-specific pleurisy, 19 tuberculous pleurisy, 16 parapneumonic effusion and one Dressler Syndrome. When these sub-groups were compared, the parapneumonic effusion subgroup CRP levels (mean 89 +/- 16.3 mg l(-1)) were significantly higher than those in the other subgroups, other exudate of neoplastic effusion, tuberculous pleurisy and chronic non-specific effusion and the transudate group (P<0.0001; P<0.0001; P<0.0004 and P<0.0001, respectively). The ratio between pleural fluid and serum CRP was significantly higher in the parapneumonic effusion subgroup than in the neoplastic subgroup (P<0.0002; 6.6 +/- 2.7 mg l(-1) and 1 +/- 0.2 mg l(-1), respectively). Pleural fluid CRP levels > 30 mg l(-1) had a high sensitivity (93.7%) and specificity (76.5%) and a positive predictive value of 98.4%. In the differential diagnosis of pleural effusions, higher CRP levels may prove to be a rapid, practical and accurate method of differentiating parapneumonic effusions from other exudate types. Although the high level of CRP obtained in the exudate group may be due to the number of patients with parapneumonic effusion who were included, the pleural CRP level may also be helpful in discriminating between exudative and transudative pleural effusions.     

C-reactive protein in lymphocytic pleural effusions: a diagnostic aid in tuberculous pleuritis

BACKGROUND: C-reactive protein (CRP) pleural fluid levels have been found to be higher in tuberculosis and parapneumonic effusions than in other causes of pleural effusion. OBJECTIVE: The aim of this study was to analyze whether CRP (a simple and inexpensive test) may be a diagnostic aid for tuberculosis in lymphocytic pleural effusions. METHODS: One hundred and forty-four patients with a lymphocytic pleural effusion (more than 50% lymphocytes in the differential white blood cell count) were included. The patients were 93 men (65%) and 51 women (35%), aged 64 +/- 18 years (mean +/- SD). The diagnoses were as follows: tuberculosis, 20; pleural effusion associated with malignancy, 69; transudates, 38; other benign exudates, 17. RESULTS: The CRP pleural fluid level was higher in tuberculous pleuritis (54 +/- 24 mg/l) than in lymphocytic effusions of other origin (21 +/- 16 mg/l; p < 0.001). High CRP levels (>or=50 mg/l) have a high specificity for tuberculosis (95%), and low levels (<30 mg/l) have a high sensitivity (95%) for excluding disease. CONCLUSIONS: CRP pleural fluid level determination is useful in the diagnostic workup of lymphocytic pleural effusions. High CRP levels are very suggestive of tuberculous pleuritis, and low CRP levels make this diagnosis unlikely.     

Diagnostic performance of adenosine deaminase activity in pleural fluid: A single-center experience with over 2100 consecutive patients

ObjectiveTo determine the diagnostic utility of adenosine deaminase (ADA) in a large series of pleural effusions of different etiologies.MethodsA retrospective study of 2104 consecutive patients presenting with pleural effusion was carried out at a Spanish university hospital. ADA levels in pleural fluid were determined using a non-Giusti automatic kinetic assay, and a receiver operating characteristics curve analysis was applied to estimate their discriminative properties.ResultsPleural tuberculosis (TB) accounted for 221 (10.5%) effusions. Pleural fluid ADA > 35 U/L yielded 93% sensitivity, 90% specificity, a positive likelihood ratio (LR) of 10.05 and a negative LR of 0.07 for the diagnosis of TB among lymphocytic exudates. The ADA activity was significantly higher in neutrophil- (111.6 U/L) than in lymphocyte-rich (62.4 U/L; p = 0.002) TB effusions. Overall, more than 40% of parapneumonics and half of lymphomatous effusions exceeded the cutoff set for TB. These were the only causes of ADA activity above 250 U/L. When the prevalence of TB as a cause of exudative effusions is low (e.g., 1%), the estimated positive predictive value of the ADA test may be as low as 7%, although the negative predictive value remains high (99.9%).ConclusionWhere available, pleural ADA should be routinely used to rule TB in or out in areas with moderate to high or low TB prevalence, respectively. A high ADA level is a characteristic not only of lymphocytic, but also of neutrophilic TB effusions. An extremely high ADA activity should raise suspicion of empyema or lymphoma.     

A simple C-reactive protein measurement for the differentiation between tuberculous and malignant pleural effusion

OBJECTIVE: The aim of this study was to determine the validity of pleural fluid C-reactive protein (CRP) concentrations and/or pleural fluid to serum CRP ratio for differentiating tuberculous pleuritis (TBP) from malignant pleural effusion (MPE) in patients presenting with lymphocytic exudative pleural effusions. METHODOLOGY: A cross-sectional study was conducted on 161 patients with pleural effusion who underwent diagnostic evaluation at Siriraj Hospital, Bangkok, Thailand, between April 2001 and March 2002. The complete biochemical analysis of pleural fluid, cultures of pleural fluid, and pathological examinations of pleural fluid and pleural tissue were performed. The CRP concentrations were then measured in stored sera and pleural fluid samples from patients with a lymphocytic exudative pleural effusion and with a definite diagnosis. RESULTS: Among the 148 patients with lymphocytic exudative pleural effusions, 55 were diagnosed with TBP, 60 with MPE, and 33 with non-specific pleuritis. Pleural fluid and serum CRP levels were significantly higher in the TBP group than in the MPE group (54.58 +/- 4.50 mg/L and 106.93 +/- 9.54 mg/L vs 12.66 +/- 3.52 mg/L and 49.66 +/- 8.84 mg/L, respectively, P < 0.001). The ratio of pleural fluid to serum CRP was significantly higher in the TBP group than in the MPE group (0.52 +/- 0.18 vs 0.30 +/- 0.16, P < 0.001). The optimum cut-off value for pleural fluid CRP level of > or =30 mg/dL had a sensitivity of 72% with 93% specificity, and the pleural fluid to serum CRP ratio cut-off value of 0.45 had a sensitivity of 60% with 89% specificity. A correlation between serum and pleural fluid CRP levels was observed in TBP patients but not in MPE patients. CONCLUSION: In patients presenting with lymphocytic exudative pleural effusion, a simple marker of raised pleural fluid CRP level may be helpful in discriminating between TBP and MPE.