Which section of the clinical laboratory focuses on organisms not visible to the naked eye?

The correct choice is the Microbiology Section, which specifically deals with the study and identification of microorganisms, including bacteria, viruses, fungi, and parasites—organisms that are not visible to the naked eye. This section employs various specialized techniques and cultures to isolate and identify these pathogens, which are crucial in diagnosing infections and guiding treatment decisions.

In contrast, the Hematology Section focuses on blood components and cellular elements, examining conditions such as anemia or blood disorders, which involve visible components under a microscope but not microorganisms. The Chemistry Section analyzes bodily fluids for chemical components, such as glucose or electrolytes, rather than focusing on microorganisms. Lastly, the Blood Bank Section handles blood products and transfusions, ensuring compatibility between donors and recipients, rather than studying microorganisms. Each of these other sections has a distinct role that does not involve the microscopic study of organisms.