Which of the following is an example of histopathology?

• A. Each organ is weighed and examined for any visible abnormalities
• B. Any visible lesion or growth is described in detail to help in diagnosis
• C. Serological tests are conducted to obtain a history of infections affecting the animal
• D. Thin slices of tissue are fixed, stained, and examined under the microscope

Answer: (D)

Histopathology is the microscopic study of tissue architecture and cellular details to diagnose disease. This requires preparing tissue by fixing it to preserve structures, cutting it into very thin sections, staining to highlight different components, and then examining these slides under a microscope to detect abnormalities.

The option described fits this process exactly: thin slices of tissue are fixed, stained, and examined under the microscope. This sequence—fixation, sectioning, staining, and microscopic evaluation—is the hallmark of histopathology and is how tissue-level disease is identified.

Other choices reflect different levels or methods of assessment. Weighing organs and describing them grossly involves macroscopic or gross pathology, which doesn’t involve microscopic tissue analysis. Describing visible lesions in detail also pertains to gross findings used for diagnosis without microscopy. Serological tests look for antibodies or antigens to assess infections, which is immunology rather than tissue architecture.