Pathology Lab Pathology is a significant component of the causal study of disease and a major field in modern medicine and diagnosis. The term pathology itself may be used broadly to refer to the study of disease in general, incorporating a wide range of bioscience research fields and medical practices, or more narrowly to describe work within the contemporary medical field of "general pathology," which includes a number of distinct but inter-related medical specialties which diagnose disease mostly through the analysis of tissue, cell, and body fluid samples. Used as a count noun, "a pathology" can also refer to the predicted or actual progression of particular diseases, and the affix path is sometimes used to indicate a state of disease in cases of both physical ailment and psychological conditions. Similarly, a pathological condition is one caused by disease, rather than occurring physiologically. A physician practicing pathology is called a pathologist.