Vázquez F, Michelángelo H, Trevisani H, González F, de Quiros B
Servicio de Clinica Médica, Hospital Italiano, Buenos Aires, Argentina.
Medicina (B Aires). 1996;56(3):223-30.
The objective was 1) to determine the usefulness of different criteria in the differential diagnosis between exudate and transudate in pleural effusion, 2) to evaluate albumin gradient changes in pleural effusion fluids characterized as transudates in patients who do and do not receive diuretic therapy, 3) to define the specificity of pleural effusions of neoplastic etiology. All patients with pleural effusion admitted to the hospital between January 15 and August 15 1994 were evaluated consecutively. Serum and pleural effusion, total protein, LDH, albumin and cholesterol levels were measured and the etiologic diagnosis of the pleural effusion (gold standard) was established. Out of the total of 112 evaluated patients, 7 were excluded because it was impossible to reach a final diagnosis. Based on the etiologic diagnosis, 47 patients (44.8%), average age of 69.6 +/- 12.07, had pleural effusions defined as transudate and 58 patients (55.2%), average age of 66.5 +/- 14.26, had pleural effusions defined as exudate. Sixty-six percent of the transudates were secondary to heart failure, while 40% of the exudates were of neoplastic origin. Using the criteria of Light et al, we obtained a diagnostic accuracy (DA) of 82.7% (CI 95% 73.1-90.0)%. However, when the cut-off point was modified according to Valdez and the value of cholesterol in pleural effusion and its relation to serum cholesterol was added, the DA rose to 90.2 (83.2-96.0)% (p < 0.05). The effusion-serum cholesterol ratio demonstrated 100 (85.1-100)% sensitivity for neoplastic effusions, whereas for non-neoplastic exudative effusions the sensitivity was 89 (73.2-96.8)%. The tests, however, showed only 17.4 (6.56-33.6)% specificity. The albumin gradient (the difference between serum and pleural effusion albumin) did no vary in patients with transudates who received diuretics, allowing a correct diagnosis of transudate in 93 (82.4-97.8)% of the cases. However, in patients who were taking diuretics, the classic criteria of protein index defined correctly only 66 (53.4-82.1)% of the cases (p < 0.05). It can be concluded that the variation of cut-off points originally established by Light et al. and the addition of cholesterol determination in pleural effusion and its relation to the serum cholesterol level allowed us to increase the DA. This appears to be the best way to differentiate a transudate from an exudate. The relation between pleural effusion and serum cholesterol levels showed a very low specificity for the differentiation of neoplastic and non-neoplastic exudative pleural effusions. Unlike the pleural effusion-serum total protein ratio, the albumin gradient allowed us to establish the correct diagnosis of transudate even in patients taking diuretics.
1）确定不同标准在胸腔积液渗出液与漏出液鉴别诊断中的作用；2）评估接受和未接受利尿剂治疗的以漏出液为特征的胸腔积液中白蛋白梯度的变化；3）明确肿瘤性病因胸腔积液的特异性。对1994年1月15日至8月15日期间收治入院的所有胸腔积液患者进行连续评估。测定血清和胸腔积液中的总蛋白、乳酸脱氢酶、白蛋白和胆固醇水平，并确立胸腔积液的病因诊断（金标准）。在总共112例接受评估的患者中，7例因无法得出最终诊断而被排除。根据病因诊断，47例（44.8%）患者平均年龄为69.6±12.07岁，其胸腔积液被定义为漏出液；58例（55.2%）患者平均年龄为66.5±14.26岁，其胸腔积液被定义为渗出液。66%的漏出液继发于心力衰竭，而40%的渗出液源于肿瘤。采用Light等人的标准，我们获得的诊断准确率（DA）为82.7%（95%置信区间73.1 - 90.0%）。然而，当根据Valdez修改截断点并加入胸腔积液中胆固醇的值及其与血清胆固醇的关系时，DA升至90.2（83.2 - 96.0）%（p < 0.05）。积液 - 血清胆固醇比值对肿瘤性积液的敏感性为100（85.1 - 100）%，而对非肿瘤性渗出性积液的敏感性为89（73.2 - 96.8）%。然而，这些检测的特异性仅为17.（6.56 - 33.6）%。白蛋白梯度（血清与胸腔积液白蛋白的差值）在接受利尿剂治疗的漏出液患者中无变化，93（82.4 - 97.8）%的病例能正确诊断为漏出液。然而，在服用利尿剂的患者中，经典的蛋白指数标准仅能正确诊断66（53.4 - 82.1）%的病例（p < 0.05）。可以得出结论，对Light等人最初确立的截断点进行修改，并加入胸腔积液胆固醇测定及其与血清胆固醇水平的关系，使我们提高了诊断准确率。这似乎是区分漏出液和渗出液的最佳方法。胸腔积液与血清胆固醇水平的关系在区分肿瘤性和非肿瘤性渗出性胸腔积液方面特异性很低。与胸腔积液 - 血清总蛋白比值不同，白蛋白梯度即使在服用利尿剂的患者中也能使我们正确诊断漏出液。
