Is a persistent low-grade fever something to worry about?

A low-grade fever lasting a few days after a clear viral illness is usually just the tail of recovery. What deserves investigation is a low-grade fever persisting beyond two weeks with no obvious cause, particularly alongside weight loss, night sweats, persistent cough, or lumps in the neck or armpit. In India that combination should raise TB specifically. Other causes worth excluding include urinary infection, thyroid problems, some medications, and inflammatory conditions. Track it with an actual thermometer at the same time each day rather than by feel, since perception of fever is unreliable.