Before starting with any treatment it is important to go through a proper diagnosis of the patient. Doctors recommend various pathological tests in order to determine the actual disease of the patient. A pathologist studies the blood samples, tissues and cells in order to determine the problem that the patient is suffering. The pathological field consists of mainly four components that include developments, consequences, structural alterations and causes. The job of a pathologist is very critical before starting with the medical case of any patient.