痰诱导是一项涵盖痰液诱导和后续处理的技术，主要用于分析气道中存在的细胞和不同炎症生物标志物，以进一步了解不同炎症性呼吸系统疾病（例如哮喘和慢性阻塞性肺疾病）的病理生理学）以及肺癌、肺结核、耶氏肺孢子虫肺炎等肺部疾病的诊断。据报道，这是一种非侵入性、安全、具有成本效益且可靠的技术，具有很高的成功率。然而，由于技术要求高、耗时且需要雇用经过培训的人员，该技术仅在有限的研究中心和有限的临床使用中心使用。诱导后收集痰液时，主要目标是获得差异细胞计数并评估气道炎症的分子生物标志物，例如嗜酸性粒细胞阳离子蛋白、嗜酸性粒细胞衍生的神经毒素、主要碱性蛋白、类胰蛋白酶、细胞因子的产生[例如白细胞介素（ IL)-5]、白蛋白和纤维蛋白原。此外，处理后的痰液中的细胞离心涂片可用于细胞产物的免疫细胞化学染色，例如 EG-2 反应蛋白、粒细胞巨噬细胞集落刺激因子、肿瘤坏死因子 α 和 IL-8，这些产物在了解癌症的病理生理学方面发挥着重要作用。炎症性气道疾病。如今，通过对痰上清液进行流式细胞术和原位杂交等额外分析，可以进一步使用该技术，以更多地研究各种呼吸道疾病的免疫反应和病理生理过程。此外，应用痰液相评估生物标志物可以更常规地用于病理实验室诊断肺癌、慢性阻塞性肺病和哮喘，以及监测肺癌进展以及哮喘和慢性阻塞性肺病治疗，从而实现早期发现和早期诊断。临床医生提供更好的治疗。© 2023 Goncalves 和 Eze。

Sputum induction is a technique that covers the induction and the subsequent processing of the expectorate primarily for the analysis of cells and different inflammatory biomarkers present in the airways to further understand the pathophysiology of different inflammatory respiratory disorders such as asthma and chronic obstructive pulmonary disease (COPD) as well as the diagnosis of lung diseases such as lung cancer, tuberculosis, and Pneumocystis jirovecii pneumonia. It is a non-invasive, safe, cost-effective, and reliable technique reported to exhibit a high success rate. However, due to being technically demanding and time-consuming and having the need of employing trained staff, this technique is only used in restricted research centres and in limited centres of clinical use. When the sputum is collected after induction, the primary goal is to obtain a differential cell count and evaluate the molecular biomarkers of airway inflammation such as eosinophil cationic protein, eosinophil-derived neurotoxin, major basic protein, tryptase, cytokine production [e.g., interleukin (IL)-5], albumin, and fibrinogen. In addition, cytospins from the processed sputum are used for immunocytochemical staining of cellular products such as EG-2 reactive protein, granulocyte-macrophage colony-stimulating factor, tumour necrosis factor alpha, and IL-8 that play significant roles in understanding the pathophysiology of inflammatory airway diseases. Nowadays, this technique can be further used by performing an additional analysis such as flow cytometry and in situ hybridisation on the sputum supernatant to investigate more the immune response and pathophysiological process of such various respiratory diseases. In addition, the application of sputum fluid phase to assess the biomarkers could be used more routinely in pathological laboratories for diagnosing lung cancer, COPD, and asthma as well as for monitoring lung cancer progression and asthma and COPD treatment, allowing for early detection and a better treatment provided by the clinicians.© 2023 Goncalves and Eze.