Final answer:
The two categories of diagnostic tests are molecular diagnostics, which include serological tests and nucleic acid tests, and medical imaging, which encompasses X-rays, CT scans, PET scans, and endoscopies.
Step-by-step explanation:
The two categories of diagnostic tests often refer to molecular diagnostics and medical imaging. Molecular diagnostics include techniques that are specific and sensitive for the target molecule, such as serological tests for antibodies and/or HIV antigens, as well as nucleic acid tests (NAT) for the presence of the virus. In contrast, medical imaging diagnostic tests, like X-rays, CT scans, PET scans, and endoscopies, utilize various forms of radiation to visualize internal structures of the body and are instrumental in detecting conditions such as cancer.