Epstein-Barr virus (EBV) is a common virus that causes infectious mononucleosis (mono) and is associated with various other health conditions. Testing for EBV antibodies is significant for several reasons. It helps diagnose acute EBV infection, confirm past exposure or immunity, and identify the cause of symptoms such as persistent fatigue or enlarged lymph nodes. Testing is particularly important in cases of suspected mono, evaluating immune status prior to organ transplantation, or investigating EBV-related complications. It aids in appropriate patient management, treatment decisions, and prevention of transmission.