Human body fluids, including blood, saliva, cerebrospinal fluid, excreta, and tissue fluids, are perceived as appealing sources for clinical biomarkers, especially in chronic diseases that seriously affect people’s daily lives. Body fluid analysis enables diagnosing diseases as well as monitoring disease markers and allows prediction of prognosis and follow-up of disease progress with low cost, low invasiveness, and rapid sample collection and processing. In addition, profiles of molecular expression level in body fluids can help reveal the alterations of physiological status and cellular networks in the diseased tissues. Therefore, body fluid analysis has become one of the most valuable tools for early detection, monitoring, management, and early response evaluation of chronic diseases, as well as unveiling the potential pathogenesis of chronic diseases.

With the application of body fluid analysis, which has been recognized as one of the most promising approaches in practice, we could explore chronic diseases such as diabetes, cancer, hypertension, and glaucoma deeper. This could aid in forming a more comprehensive understanding of the mechanisms of physiology and pathology in chronic diseases, which may play a critical role in providing early proof, directing more effective care, and better patient outcomes.

In this Special Issue, we invite investigators to contribute original research and review articles relating to the application of body fluid analysis to chronic diseases as well as cutting-edge reviews relevant to this topic. We hope that this will stimulate continuing efforts to understand how body fluid analysis facilitates early diagnosis and optimized treatment of chronic diseases, as well as clarifying the underlying pathological mechanism.

Potential topics include but are not limited to the following:

• Chronic disease related biomarkers in body fluid
• Body fluid alterations in chronic diseases
• The development of novel technology of body fluid analysis in chronic diseases
• New advances in body fluid analysis for prediction, monitoring, and early response evaluation of chronic diseases
• Novel treatments based on body fluid analysis in chronic diseases
• Sample collection and preparation of body fluid
• Human body fluid and bioinformatics