Laboratory findings include severe anemia, increased mean corpuscular volume (MCV, due to the presence of a large number of young erythrocytes), and hyperbilirubinemia (from increased red cell destruction) that can be of the conjugated or unconjugated type. Diagnosis is made by a positive direct Coombs test, other lab tests, and clinical examination and history. The direct Coombs test looks for antibodies attached to the surface of red blood cells.