PI IgG, also known as Paroxysmal Nocturnal Hemoglobinuria (PNH) type III protein, is commonly associated with a rare blood disorder. This disorder is caused by a lack of protein protection on red blood cells, leading to their premature destruction, and subsequent anemia. Synonyms for the term PI IgG include anti-CD55, anticomplement, C8-binding protein, complement-control protein, decay-accelerating factor CD55, and DAF. While these terms may not be interchangeable with PI IgG in all contexts, they all relate to the same underlying cause and are important for understanding and diagnosing this condition. Individuals with PNH require prompt and specialized medical care to manage their symptoms and prevent complications.