Emerging diagnostic techniques in sarcoidosis: a path forward.

Sarcoidosis is a complex and heterogenous disease of which the diagnosis is based on clinical and radiological findings, histopathology showing non-caseating granulomas, and exclusion of other granulomatous diseases. Several tools are well established in the diagnostic pathway, such as pulmonary function tests, broncho-alveolar lavage, endobronchial ultrasound-guided transbronchial needle aspiration, transbronchial and endobronchial biopsies, the serum biomarkers serum angiotensin converting enzyme and soluble interleukin-2 receptor, and imaging, mainly chest computed tomography (CT), 18-fluorodeoxyglucose-positron emission tomography/CT, and brain and cardiac magnetic resonance imaging. However, continuous efforts in the field have been made, and a variety of novel methods are arising. These might be less invasive, can lead to a more secure diagnosis, promote risk stratification, or guide treatment decisions, especially when combined in a stepwise multimodal approach. In this work, we aim to give an overview of the current diagnostic standards in sarcoidosis and discuss the new kids on the block.