In the average adult male there are approxitely 5 quarts (4.75 liters) of blood, composed of about 3 quarts (2.85 liters) of plasma and 2 quarts (1.9 liters) of cells.
Blood cells are suspended in the plasma, which is made up of water and dissolved materials, including hormones, antibodies, and enzymes that are being carried to the tissues, and cellular waste products that are being carried to the lungs and kidneys.
The major blood cells are classified as red cells (erythrocytes), white cells (leukocytes), and platelets (thrombocytes).
The red cells are delicate, round, concave bodies that contain hemoglobin, the complex chemical that transports oxygen and carbon dioxide.
Hemolysis occurs when the thin protective membrane that encases the fragile red cells is ruptured, allowing hemoglobin to escape into the plasma. Hemolysis can be caused by rough handling of a blood specimen, leaving the tourniquet on too long (causing blood stasis) or squeezing the tip of the finger too hard during capillary collection, dilution, exposure to contaminants, extremes in temperature, or pathologic conditions.
