How does a pathologist make a diagnosis?
The microscope is the main diagnostic tool used in surgical pathology and cytopathology. Thinly-sliced samples of tissue or cells are placed on rectangular sheets of glass measuring 3 x 1 inches (“glass slide”), and these tissues or cells are stained with various dyes to make the cells and tissue architecture visible and to bring out diagnostic features. By careful microscopic examination under various magnifications (from 40 to 1000 times enlargement), the structure of the tissues or cells can be evaluated for changes that indicate disease. It takes many years of experience to learn to distinguish normal cells and tissues from abnormal, and to identify the disease process correctly. In difficult cases, pathologists use a variety of more sophisticated tools to detect organisms, molecules or genes that may identify the disease process. For example, antibodies (proteins that bind to specific molecules) can be used to reveal the presence of a virus which is too small to be seen using the
