胸腔积液是由各种病因所致的胸膜腔积液，其只是疾病的临床表现和体征，并非是一种疾病，因此胸腔积液的诊断并非确诊的终点，而病因诊断才是最终目的。胸腔积液的病因复杂多样，形成机制千变万化，因此病因诊断也非常困难。在临床中渗出液、漏出液的分析，良性、恶性胸腔积液的鉴别，应遵循优先无创检查，必要时有创检查的原则。在整个诊断思路中，恰当的应用整体、辨证的哲学思维正是诊断学的艺术所在。

Pleural effusion is characterized by the pleural cavity filled with fluids, and it is developed by various etiologies.Pleural effusion is not a disease, but the clinical manifestations and signs of the diseases.Therefore, it is not the end that we get the diagnosis of pleural effusion, while it is our ultimate goal to find the etiologies.Both the etiologies and mechanisms of pleural effusion are complicated, so it is very difficult to confirm the ultimate diagnosis. In clinical practice, it would be essential for diagnosis process that includes the analysis of transudative or exudative effusion, the differentiation of benign and malignant effusion, the noninvasive examination in priority, and the invasive examination in necessity.The appropriate application of the integral and dialectical thinking is the art in the diagnostic consideration.