A complete blood count with differential (CBC with diff) is a comprehensive blood test that provides detailed insights into the composition of your blood. It assesses various components, including red blood cells, white blood cells, and platelets, along with a breakdown of the different types of white blood cells. The red blood cell count and size can help diagnose conditions like anemia or polycythemia, while the total white blood cell count indicates the presence of infection or inflammation. The differential count, which analyzes the percentages of different white blood cell types, can reveal abnormalities associated with infections, autoimmune disorders, and more. Additionally, platelet levels are assessed to identify bleeding or clotting disorders.