Final answer:
The direct Coombs' test is used to detect antibodies that bind to a person's own red blood cells. It can identify various conditions such as autoimmune diseases and infectious diseases. It is also used to detect certain cancers and drug allergies.
Step-by-step explanation:
The direct Coombs' test is designed to detect when people have a disease that causes them to produce antibodies that bind to their own red blood cells. This test is used to identify conditions such as hemolytic transfusion reactions, autoimmune hemolytic anemia, infectious mononucleosis, syphilis, and Mycoplasma pneumonia. It can also indicate the presence of some cancers and allergic reactions to certain drugs.