Final answer:
The buffy coat, containing leukocytes and platelets, separates plasma and red blood cells in anticoagulated tubes after the process of centrifugation.
Step-by-step explanation:
The plasma and red blood cells in anticoagulated tubes are separated by a thin, pale layer known as the buffy coat. This layer contains leukocytes (white blood cells) and platelets, and it acts as a barrier between the denser red blood cells and the lighter plasma after the blood sample has been centrifuged. The process of centrifugation involves spinning the blood at high speeds (typically over 3000 rpm), which forces the separation of the blood's components based on their density. The plasma, which makes up about 55% of blood content, is situated above the buffy coat and includes 90 percent water along with substances such as coagulation factors and antibodies. Below the buffy coat are the erythrocytes or red blood cells, which make up about 45% of the blood.