Presented are laboratory studies focusing on blood cells and the complete scheme of blood coagulation. Formed is the basis for the following types of laboratory operations: (1) distinguishing the morphology of normal and abnormal blood cells; (2) measuring the concentrations or number of blood cells; (3) measuring concentration and detecting abnormalities of hemoglobin; (4) measuring defects in coagulation; and (5) performing a few specific disease-related tests which involve blood cells. Types of equipment needed, actual stepwise performance of tests, and reagents needed, as well as established minimum levels of accuracy are included. (Author/CS)