This lecture will explore the crucial role of immunoglobulins (Ig) in clinical practice, focusing on their structure, function, and diagnostic significance. The session will cover the five classes of immunoglobulins—IgG, IgA, IgM, IgE, and IgD—highlighting their distinct roles in immune defense. Students will learn how to utilize immunoglobulin levels and specific antibodies to diagnose and manage infections, autoimmune diseases, and immunodeficiencies