How do pathologists determine the causes of diseases?

Pathologists determine the causes of diseases by analyzing structural and functional changes in the body through a variety of laboratory and clinical methods. Their work is fundamental to medical diagnosis, as they correlate clinical symptoms with physical evidence to understand disease processes.1

Key methods used by pathologists include:

• Laboratory Analysis: Pathologists examine specimens such as surgically removed tissues, blood, urine, and other body fluids. They utilize tools like microbial cultures to identify infections and biopsy procedures to sample internal organs.1
• Microscopic and Chemical Examination: Using electron microscopes and specialized chemical stains, pathologists can define subcellular structures and identify tissue composition. Histology and histochemistry allow for the detailed study of tissue organization and chemical identification of substances within them.12
• Molecular Evaluation: Modern diagnostics include DNA sequencing and polymerase chain reaction (PCR) to identify genetic mutations, tumor markers, and molecular signatures that reveal the underlying causes of conditions like cancer.3
• Autopsy: Through the autopsy, pathologists reconstruct the final stages of a person's life, correlating clinical findings with anatomical observations to establish the mechanisms of disease.14