血管内皮细胞生长因子C与腺苷脱氨酶联合检测在胸腔积液鉴别诊断中的意义

目的 了解血管内皮细胞生长因子C(VEGF-C)及腺苷脱氨酶(ADA)在不同原因胸腔积液中的表达,并探讨通过比值构建联合诊断对胸腔积液鉴别诊断的作用.方法 选择143例临床确诊的胸腔积液患者(恶性胸腔积液40例,结核性胸膜炎45例,其他类型58例),采用双抗夹心ELISA法检测胸水VEGF-C,采用速率法检测胸水ADA,计算VEGF-C/ADA比值,比较不同类型胸腔积液患者中上述诊断指标的变化,并计算它们的敏感度、特异度和准确度.结果 恶性胸腔积液中VEGF-C浓度高于结核性胸腔积液及类肺炎性等其他类型胸腔积液,(286.32±102.65)ng/L vs(133.46±39.83)ng/L,(140.14±44.62)ng/L,P<0.05.结核性胸腔积液中ADA浓度高于恶性胸腔积液及其他类型胸腔积液,(78.6±36.3)IU/L vs(23.4±11.2)IU/L,(26.1±10.5)IU/L,P<0.05.VEGF-C/ADA≥8对恶性胸腔积液诊断的敏感度为87.5%,特异度为81.4%;VEGF-C/ADA≤3对结核性胸腔积液诊断的敏感度为84.4%,特异度为86.4%.结论 VEGF-C与ADA浓度比值对胸腔积液的鉴别诊断具有较好的临床价值.     

High adenosine deaminase activity in the pleural effusion of a patient with Legionnaires' disease

Abstract:   Although Legionnaires' disease (LD) is frequently accompanied by pleural effusion, the characteristics of pleural effusions in LD have not been well studied. Levels of adenosine deaminase (ADA) activity in pleural fluid >40 IU/L have a high sensitivity (81–100%) and specificity (83–100%) for tuberculosis. ADA activity in pleural effusions due to LD has not been previously reported. The case of a patient with LD complicated by a pleural effusion with high ADA activity is reported. In countries where the prevalence of tuberculosis is high and pleural fluid ADA activities are frequently measured, LD should be included in the differential diagnosis of an exudative pleural effusion with high ADA activity.     

Adenosine deaminase activity in pleural fluid--a diagnostic test of tuberculous pleural effusion.

Adenosine deaminase (ADA) activity in pleural fluids was studied in 47 patients with pleural effusion of different etiology. Patients were divided into two groups: Group I - Tuberculous pleural effusion (21 patients): Group II - Non tuberculous effusion (26 patients) and these included malignant pleural effusion (9 cases), synpneumonic pleural effusion (9 cases) and transudative pleural effusion (8 cases). The mean ADA activity was 64.67 IU/L +/- 21.68 in group I and 6.99 +/- 3.69 in Group II. Increased mean pleural fluid ADA activity in tuberculous pleural effusion was highly significant (p < 0.001) when compared with pleural effusion of non-tuberculous etiology. Based on lowest value of ADA activity found in tuberculous pleural effusion (30 IU/L), the test has a sensitivity and specificity of 1.     

腺苷脱氨酶诊断结核性胸膜炎价值的再评价

目的 探讨胸腔积液和血清中腺苷脱氨酶(ADA)对鉴别结核性胸膜炎及恶性胸腔积液的临床价值.方法 回顾性分析91例经内科胸腔镜胸膜活检病理确诊为结核性胸腔积液(结核组49例)和恶性胸腔积液(恶性组42例)患者的胸腔积液及血清中ADA活性,应用受试者工作曲线(ROC曲线)确定结核性胸膜炎患者胸腔积液ADA的最佳临界值.结果 结核组胸腔积液ADA活性和胸腔积液ADA与血清ADA比值分别为(46±26)U/L和4.1±4.0,明显高于恶性组的(16±8)U/L和1.7±1.2,差异均有统计学意义(t值分别为7.383和3.852,均P＜0.01),结核组和恶性组的血清ADA活性分别为(13±5)U/L和(12±6)U/L,差异无统计学意义(t=1.582,P＞0.05).应用ROC曲线确定胸腔积液ADA诊断结核性胸膜炎的最佳临界值为28.7 U/L,灵敏度为75.5%,特异度为95.2%.结论 胸腔积液ADA活性可以作为鉴别结核性和恶性胸腔积液的重要指标,对结核性胸膜炎有较高的临床诊断价值,而血清ADA活性对鉴别两者无临床意义.     

ADA、IFNγ-、sIL-2R检测在鉴别结核性和癌性胸水中的价值

目的研究腺苷脱氨酶（ADA）、γ干扰素（IFN-γ）、可溶性白介素2受体（sIL-2R）对结核性胸水和癌性胸水鉴别诊断的价值。方法采用酶法和ELISA方法检测47例结核性胸水患者和47例癌性胸水患者胸水中ADA活性和IFNγ-、sIL-2R水平。结果结核性胸水组的ADA（72.3±21.7 U/L）、IFN-γ（481.3±257.1 pg/m l）和sIL-2R（611.0±184.4 pmol/L）都显著高于癌性胸水组（P〈0.01）;当以ADA≥46.8 U/L、IFNγ-≥209.0 pg/m l和sIL-2R≥491.5 pmol/L为临界值,三项指标对结核性胸水的敏感度分别为93.6%,87.2%,70.2%;特异度分别为91.5%,91.5%,78.7%。结论胸水中ADA、IFN-γ和sIL-2R对结核性胸水和癌性胸水的鉴别诊断都有较高的临床价值。     

胸水ADA、TB-DNA联合检测在结核性胸膜炎中的诊断运用

目的分析胸水ADA、TB-DNA联合检测对结核性胸膜炎诊断运用价值。方法对我院收治的结核性胸膜炎患者183例、癌性胸水患者65例以及炎性胸水患者49例作为研究对象,分别进行ADA、TB-DNA的检测,并对ADA、TB-DNA在三种疾病中的阳性率以及对结核性胸膜炎的敏感度、特异性以及准确性进行分析。结果结核性胸膜炎患者的ADA含量(72.3±23.2 IU/L)明显高于炎性胸水患者(38.4±12.9 IU/L)以及癌性胸水患者(24.3±6.5 IU/L);ADA、TB-DNA联合检测对结核性胸膜炎的特异性84.2%,敏感性98.91%以及准确性为93.26%。结论对结核性胸膜炎患者采用胸水ADA、TB-DNA联合检测可明显提高其检出率,并有助于对结核性胸膜炎胸水、癌性胸水以及炎性胸水的鉴别。     

Diagnostic utility of adenosine deaminase (ADA) activity in pleural fluid and serum of tuberculous and non-tuberculous respiratory disease patients

Adenosine deaminase activity (ADA) was assayed in pleural fluid and serum of 42 subjects with pleural effusion. Twenty-nine of them had TB pleural effusion and the remaining 13 had pleural effusion due to non-TB respiratory diseases. Serum adenosine deaminase activity were also measured in 32 pulmonary tuberculosis patients without pleural effusion and equal numbers of healthy controls without systemic diseases for comparative analysis. The patients attending the medicine out-patient department (MOPD) of the B. P. Koirala Institute of Health Sciences, Dharan, Nepal were taken as study subjects. Serum and pleural fluid ADA activities were assayed spectrophotometrically by the method of Guisti and Gallanti. The mean serum ADA activity was significantly increased in patients with tubercular pleural effusion (34.53 +/- 10.27 IU/l) compared to pulmonary tuberculosis patients without pleural effusion (26.54 +/- 4.76 IU/l), (p = 0.004), those with non-TB respiratory disease (16.71 +/- 5.16 IU/l), (p = 0.0001) and healthy controls (15.53 +/- 4.4 IU/l) (p = 0.0001). The mean ADA in the pleural fluid of tubercular pleural effusion patients (90.29 +/- 54.80 IU/l) was significantly higher compared to those with non-TB respiratory disease (24.43 +/- 9.28 IU/l) (p = 0.0001). Using the lowest cutoff value for enzyme activity in the serum of patients with TB pleural effusion (25 IU/l), a test sensitivity of 72.41% and specificity of 81.53% were obtained. Using the lowest cutoff value for enzyme activity in pleural fluid of patients with TB pleural effusion (45 IU/l) the sensitivity and specificity for diagnosis were 76.10% and 100%, respectively. Therefore, the measurement of ADA in tubercular pleural effusion has a utility in the diagnosis of tuberculosis when other clinical and laboratory tests are negative.     

干扰素γ、白细胞介素12及腺苷脱氨酶同工酶对结核性胸腔积液的诊断价值

目的　研究胸腔积液中干扰素γ(IFN γ)和白细胞介素 12 (IL 12 )的浓度及腺苷脱氨酶同工酶 (ADA2 )的活性三者在结核性胸腔积液诊断中的临床价值。方法　以 2 0 0 2年 3月～ 2 0 0 3年2月期间在北京大学人民医院、北京胸科医院、北京结核病胸部肿瘤研究所等医院的未经治疗的胸腔积液患者为研究对象 ,其中结核性胸腔积液 14 1例、恶性胸腔积液 4 9例。应用酶速率法检测胸腔积液标本中腺苷脱氨酶 (ADA)、ADA2 的活性 ,酶联免疫吸附测定 (ELISA)检测IFN γ和IL 12的浓度。比较两组胸腔积液中ADA和ADA2 活性 ,以及IFN γ和IL 12浓度之间的区别。结果　 (1)结核性胸腔积液组ADA、ADA2 活性分别为 (5 1 6± 10 9)U/L和 (4 7 9± 6 9)U/L ,恶性胸腔积液组ADA、ADA2 活性分别为 (2 0 4± 4 4 )U/L、(13 2± 3 2 )U/L ,结核性胸腔积液组的ADA、ADA2 活性显著高于恶性胸腔积液组 (P <0 0 1)。结核性胸腔积液组IFN γ和IL 12浓度分别为 (112 1± 4 5 8)ng/L及 (10 4 3± 32 3)ng/L ,恶性胸腔积液组IFN γ和IL 12浓度分别为 (2 4 8± 5 9)ng/L和 (6 1 8±10 8)ng/L ,结核性胸腔积液组的IFN γ和IL 12浓度水平显著高于恶性胸腔积液组 (P <0 0 1,0 0 5 ) ;(2 )ROC曲线分析结果 ,IFN γ以 6 1 7ng/L为诊     

Diagnostic value of adenosine deaminase in nontuberculous lymphocytic pleural effusions.

Adenosine deaminase (ADA) can aid in the diagnosis of tuberculous pleural effusions, but false-positive findings from lymphocytic effusions have been reported. The purpose of this study is to assess the ADA levels in nontuberculous lymphocytic pleural effusions (lymphocyte count > 50%) of different aetiologies. Altogether, 410 nontuberculous lymphocytic pleural fluid samples were consecutively selected. These included malignant effusions (n = 221), idiopathic effusions (n = 76), parapneumonic effusions (n = 35), postcoronary artery bypass graft surgery effusions (n = 6), miscellaneous exudative effusions (n = 21) and transudative effusions (n = 51). The ADA level reached the diagnostic cut-off for tuberculosis (40 U x L(-1)) in seven of the 410 cases (1.71%). The negative predictive value of ADA for the diagnosis of pleural tuberculosis was 99% (403 of 407 cases) in the group of lymphocytic pleural effusions. In five of these seven patients ADA1 and ADA2 were measured, and in all these cases (100%) ADA1/ADA(p) correctly classified these lymphocytic effusions as nontuberculous (ratio < 0.42). This prospective study provides additional evidence that adenosine deaminase levels in nontuberculous lymphocytic pleural effusions seldom exceed the cut-off set for tuberculous effusions. The pleural fluid adenosine deaminase levels were significantly higher in different types of exudative effusions than in transudates. An adenosine deaminase level < 40 IU x L(-1) virtually excluded a diagnosis of tuberculosis in lymphocytic pleural effusions. Adenosine deaminase1/adenosine deaminase(p) correctly classified all nontuberculous lymphocytic pleural effusions with high adenosine deaminase levels.     

Adenosine deaminase levels in nontuberculous lymphocytic pleural effusions

OBJECTIVES: Adenosine deaminase (ADA) can aid in the diagnosis of tuberculous pleural effusions, but false-positive findings from lymphocytic effusions have been reported. We studied the ADA levels in a variety of nontuberculous lymphocytic effusions and analyzed the relationships between ADA and conventional hematologic and biochemical parameters. METHODS: One hundred six lymphocytic pleural fluid samples (lymphocyte count > 50%) were analyzed. These included post-coronary artery bypass grafting (CABG) effusions (n = 45), malignant effusions (n = 27), miscellaneous exudative effusions (n = 10), and transudative effusions (n = 24). ADA levels were determined using the Giusti method. In 22 randomly selected cases, ADA was measured again on the same sample 6 weeks later. RESULTS: The ADA level reached the diagnostic cutoff for tuberculosis (40 U/L) in only three cases (2.8%): two lymphomas and one complicated parapneumonic effusion. There was no significant correlation between effusion ADA levels and the total leukocyte (r = 0.08), differential lymphocyte (r = 0.18) or monocyte (r = - 0.18) counts. ADA levels were significantly lower in the transudative effusions (7.2 +/- 3.5 U/L) than in post-CABG (16.6 +/- 7.2 U/L), malignant (15.3 +/- 11.2 U/L), and other exudative (15.4 +/- 13.1 U/L) effusions (p < 0.001). ADA measurements were consistent when assayed 6 weeks apart (r = 0.95; p < 0.00001; coefficient of variation, 14%). CONCLUSIONS: ADA levels in nontuberculous lymphocytic effusions seldom exceeded the diagnostic cutoff for TB. Effusion ADA levels cannot be predicted from total or differential leukocyte counts. Post-CABG pleural fluids had ADA levels similar to other nontuberculous lymphocytic effusions. ADA is stable in effusion fluids, and its measurement is reproducible.     

白介素27和腺苷脱氢酶单独及联合检测对结核性胸膜炎诊断价值

目的 探讨白介素27((interleukin-27,IL-27)和腺苷脱氨酶(adenosine deaminase,ADA)单独检测及两者联合检测结果对结核性胸膜炎和恶性肿瘤所致胸腔积液的鉴别诊断价值。方法 选取2017年12月1日至2018年7月29日福建省福州肺科医院收治的胸腔积液患者101例,通过闭式胸膜活检、内科胸腔镜检查获得病理学证据或者痰/胸腔积液分枝杆菌培养阳性及菌种鉴定结果。根据诊断结果分为结核性胸膜炎患者61例(结核组);恶性肿瘤所致胸腔积液患者40例(恶性组),其中肺黏膜相关淋巴瘤1例,恶性胸膜间皮瘤1例,肺黏液表皮样癌1例,非霍奇金淋巴瘤1例,小细胞肺癌3例,肺腺癌33例。采用酶联免疫吸附法检测两组患者胸腔积液中的IL-27和ADA的含量并进行统计学分析。应用受试者工作曲线(ROC)确定IL-27和ADA检测结果对鉴别结核性胸膜炎与恶性肿瘤所致胸腔积液的最佳临界值,并进一步分析IL-27与ADA联合检测(串联试验、并联试验)对于诊断结核性胸膜炎的价值。结果 结核组患者胸腔积液中检测到的IL-27和ADA浓度分别为[409.48(229.04,954.97)]ng/L和(45.88±14.33)U/L,明显高于恶性组[分别为115.74(77.72,161.97)ng/L和10.50(7.00,15.00)U/L],差异均有统计学意义(Z=3.139,P<0.01;t=4.006,P<0.01)。绘制ROC曲线确定IL-27鉴别结核性胸腔积液与恶性胸腔积液诊断的最佳临界值为176.31ng/L,敏感度和特异度分别为85.25% (52/61)和82.50% (33/40);ADA鉴别结核性胸腔积液与恶性胸腔积液诊断的最佳临界值为28U/L,敏感度和特异度分别为93.44% (57/61)和87.50% (35/40)。串联试验方法联合检测,特异度(95.00%,38/40)较单独检测IL-27(82.50%,33/40)及单独检测ADA(87.50%,35/40)均明显升高,并有较好的敏感度(81.97%,50/61);并联试验方法联合检测,敏感度(96.72%,59/61)较单独检测IL-27(85.25%,52/61)及单独检测ADA(93.44%,57/61)均明显升高,但特异度较低(75.00%,30/40)。结论 胸腔积液中IL-27和ADA对结核性胸膜炎的诊断均有较高价值;IL-27和ADA串联试验有助于结核性和恶性肿瘤所致胸腔积液的鉴别诊断。     

ADA检测在淋巴细胞性胸腔积液中的应用价值

目的 研究不同病因产生的淋巴细胞性胸腔积液腺苷脱氨酶(ADA)值的差异，及其与传统的血液生化学参数之间的相互关系。方法 分析l05例淋巴细胞性胸水中的ADA值，其中包括结核性50例、恶性肿瘤性40例、漏出性l5例。结果 以40U/L作为诊断结核的阳性分割值，其特异性为98．2％、敏感性为89．0％；ADA值与白细胞总数、淋巴细胞百分比、中性粒细胞百分比、LDH、蛋白的含量无关。恶性胸水的ADA值与漏出性胸水比较无差异。结论 ADA检测对结核性胸腔积液具有相当高的特异性(98．2％)，但敏感度较低为(89．0％)。血液生化学参数与ADA值的大小无明显相关性。     

Determination of adenosine deaminase activity and its isoenzymes for diagnosis of pleural effusions

OBJECTIVE: We aimed to investigate adenosine deaminase (ADA) activity and the activities of its ADA1 and ADA2 isoenzymes in pleural effusions and also sera with different aetiological origins. METHODOLOGY: The pleural effusions of 87 patients were examined. The patients were separated into four groups: transudates, parapneumonic, malignant, and tuberculous effusions. The cases were also designated as tuberculous or non-tuberculous group. Adenosine deaminase activity was determined by the colorimetric method described by Giusti and Galanti. RESULTS: The intermean differences were statistically significant for total ADA, ADA1 and ADA2, except for pleural fluid ADA1 in the malignant group when compared to the tuberculous effusion group. The intermean differences between the tuberculous and non-tuberculous group were statistically significant for all three parameters except for pleural fluid and serum ADA1 activity. The sensitivities of total ADA, ADA1 and ADA2 activities for tuberculosis were 91, 57 and 93%, respectively; their specificities 89, 88 and 92%, respectively; their positive predictive values 82, 70 and 86%; and their diagnostic accuracies 89, 76 and 92%, respectively, in pleural fluid. CONCLUSIONS: Determination of ADA and its isoenzymes can help to differentiate the causes of pleural effusion. Increased ADA2 activity is a striking marker of tuberculous effusions. In contrast, increased ADA1 activity was significantly elevated in parapneumonic effusions.     

结核性与癌性胸腔积液的实验室检测比较研究

目的比较研究实验室检测腺苷脱氨酶(ADA)、乳酸脱氢酶(LDH)、癌胚抗原(CEA)、蛋白(TP)、葡萄糖(GLU)等多项指标对结核性与癌性胸腔积液的鉴别诊断价值。方法对151例明确诊断为结核性或癌性胸腔积液分别测定胸水ADA、LDH、CEA、TP、GLU和血清TP,并进行统计分析。结果结核性胸腔积液中ADA、LDH、TP含量都明显高于癌性胸腔积液,其中胸水ADA以28U/L作为诊断结核性胸水的临界值则其敏感性和特异性均极高,结核性胸水中GLU含量则低于癌性胸水,癌性胸水CEA的阳性率高达76.0%,而结核性胸水CEA均阴性。结论联合检测胸水ADA、LDH、CEA、TP和GLU可以作为结核性与癌性胸腔积液的诊断和鉴别诊断依据,其中ADA28U/L可以考虑作为结核性胸腔积液的单独诊断依据。     

ADA在结核性胸腔积液中诊断意义

目的比较结核性胸水ADA和非结核性胸水ADA活性差异和诊断阳性率，并观察不同年龄组结核性胸水中ADA活性水平和诊断的阳性率。方法对80例结核性胸水患者和48例的非结核性胸水ADA进行分析，并以60岁为界限分为两组，进行组间ADA活性和诊断结核阳性率比较。结果结核性胸水患者中ADA活性高于非结核性胸水患者的ADA，并且ADA诊断结核性胸膜炎的阳性率高于后者。另外，结核性胸水ADA在不同年龄组间无显著性差异。结论：胸水中ADA的检测对结核性胸水的临床诊断有较大帮助。     

A prospective study of sensitivity and specificity of adenosine deaminase estimation in the diagnosis of tuberculosis pleural effusion

We prospectively evaluated the usefulness of adenosine deaminase [ADA] estimation in the diagnosis of tuberculosis [TB] pleural effusion. Seventy five subjects with pleural effusion were studied. Forty eight of them had TB pleural effusion [M:F: 37:11; mean age 33 +/- 14.4 years range 17-76] and the remaining 27 had pleural effusion due to causes other than TB [non-TB group] [M:F: 19:8; mean age 47.3 +/- 16.5 years; range 17-75]. Pleural fluid [PF] ADA levels were significantly higher in TB (n=48; mean 95.8 +/- 57.5 IU/L) compared with non-TB group (n=27; mean 30.7 +/- 27.2 IU/L) [p<0.001]. Serum ADA [S-ADA] levels were also significantly higher in TB (n=45; mean 39.6 +/- 18.3 IU/L) compared with non-TB group (n=26; mean 18.0 +/- 13.7 IU/L) [p<0.001]. PF-ADA levels were higher compared to S-SDA in TB (p <0.001) and non-TB groups [p<0.01]. Using a cut off of 35 IU/L, the sensitivity and specificity of PF-ADA in the diagnosis of TB was computed to be 83.3% and 66.6% respectively. At a cut-off level of 100 IU/L, PF-ADA was found to have a sensitivity 40% and specificity 100%. From this study it is concluded that, using 100 IU/L as the cut-off, it is possible to avoid pleural biopsy to ascertain the diagnosis of TB in as much as 40% of the patients.     

Parapneumonic effusions and empyema

Nearly 50 per cent of patients with acute bacterial pneumonia have an accompanying pleural effusion (parapneumonic effusion). With appropriate antibiotic therapy, the pleural effusion will resolve along with the pneumonia in the majority of patients. However, in a small fraction, the pleural effusion will not resolve unless drainage of the pleural space is instituted. Such patients are said to have complicated parapneumonic effusions. It is important to identify patients with complicated parapneumonic effusions as early as possible, since tube drainage of the pleural space becomes increasingly difficult the longer its institution is delayed. The possibility of a complicated parapneumonic effusion should be considered in every patient with bacterial pneumonia. If both diaphragms cannot be distinctly identified throughout their length on the lateral chest radiograph, decubitus chest radiographs should be obtained. If the thickness of the fluid on the decubitus radiograph is greater than 10 mm, a diagnostic thoracentesis should be performed. Only pleural fluid analysis can identify patients with complicated parapneumonic effusions. Complicated parapneumonic effusions are characterized by low pleural fluid pH and glucose levels, a high pleural fluid LDH, and a positive Gram stain of the pleural fluid. Tube thoracostomy should be performed immediately in a patient with an acute bacterial pneumonia if the pleural fluid glucose is below 40 mg per 100 ml, the pleural fluid pH is below 7.00, or if the Gram stain of the pleural fluid is positive. Patients with pleural fluid pH above 7.20, pleural fluid LDH below 1000 IU per L, and pleural fluid glucose levels above 40 mg per 100 ml respond well to only the administration of appropriate antibiotics.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of pneumonia due to Mycoplasma pneumoniae accompanying high adenosine deaminase activity in pleural effusion]

We experienced a 5-year-old male case of Mycoplasma pneumoniae pneumonia accompanying Adenosine Deaminase (ADA) activity in pleural effusion. Chest roentgenograms revealed the infiltration in the left upper lung field and the left pleural effusion. In serum, the M. pneumoniae CF titer increased to 1:512. The pleural effusion was yellowish in color, with a specific gravity of 1.030, protein 3.7 g/dl, glucose 101 g/dl, and ADA 50 IU/l. Pleural effusion accompanying M. pneumoniae pneumonia is rare, and the high ADA activity in this case has been reported only in one other case. This is a report of a high activity of ADA in the pleural fluid by M. pneumoniae pneumonia.     

Evaluation of polymerase chain reaction for detection of Mycobacterium tuberculosis in pleural fluid

OBJECTIVES: Tuberculosis, a reemergent killer, is threatening to assume serious proportions all over the world, particularly in view of the AIDS pandemic. The detection of mycobacterial DNA by polymerase chain reaction (PCR) in clinical samples is a promising approach for the rapid diagnosis of tuberculous infections. The aims of this study were to evaluate PCR for detection of Mycobacterium tuberculosis in pleural fluids and to correlate the results with adenosine deaminase activity (ADA) estimation and acid-fast bacilli (AFB) screening. METHODS: The sensitivity and specificity of PCR in detection of mycobacterial DNA in 20 samples of tuberculous pleural effusion were evaluated using 40 samples of nontubercular pleural effusion as controls. The results were correlated with the ADA in all 60 pleural fluids. In addition, AFB detection by Ziehl-Neelsen staining on cytospin smears of all pleural fluids was also compared. RESULTS: Of the 20 samples of tuberculous pleural effusion, mycobacterium could be detected by AFB staining in 4 samples. Fourteen samples were PCR positive. None of the samples from the control group were AFB or PCR positive. The sensitivity of PCR, therefore, was 70.0% with specificity of 100% (positive predictive value, 100%; negative predictive value, 86.95%). The sensitivity of AFB screening was at best 20%. The mean of ADA values in tubercular pleural effusions was 63.21 U/L (SD, 33.01), and the mean in the control samples was 51.1 U/L (SD, 29.71). Taking a cut-off value of 50 U/L, both the sensitivity and specificity of ADA estimation in diagnosing tuberculosis were only 55%. CONCLUSION: PCR represents a rapid and sensitive method for the detection of mycobacterial DNA in tuberculous pleural effusions. AFB screening has low sensitivity, and ADA estimation has both low sensitivity and specificity. Therefore, when the clinical suspicion is high and smear result is negative, but the signs and symptoms of M tuberculosis are apparent, PCR is the method of choice for identifying the infection.     

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.