Hematology is the study of blood, blood forming organs, and blood diseases. Red blood cells, white blood cells, and platelets make up the formed elements of blood. The most commonly performed hematology test is the complete blood count (CBC) which includes; white blood cell count, count, hemoglobin level, and several parameters of red blood cells including counts and morphology. Coagulation is a sub-specialty of hematology; basic general coagulation tests are the prothrombin time (PT) and partial thromboplastin time (PTT).
Fluid cytology is the microscopic examination of fluid in a body space, such as around the lungs (pleural), in a joint, in a cyst, or from the abdomen. It can be used to diagnose disease, or interpret cells in the fluid for abnormalities such as cancer.