What components are included in a complete blood count (CBC)?

A complete blood count (CBC) is a comprehensive blood test used to evaluate a person's overall health and detect a variety of disorders, such as anemia, infection, and many other diseases. The components typically included in a CBC are red blood cells, white blood cells, and platelets.

Red blood cells (RBCs) are crucial for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide for exhalation. White blood cells (WBCs) are essential for the immune response, helping the body fight infections and other diseases. Platelets play a vital role in blood clotting, facilitating hemostasis and preventing excessive bleeding.

The other components mentioned in the other options, such as blood plasma, antibodies, lymphocytes, plasma proteins, and electrolytes, are not considered part of the standard CBC. While some of these components may be evaluated in other tests, the primary focus of a CBC is on the counts and characteristics of red and white blood cells along with platelets, making option A the correct and complete answer.