If blood platelets removed from blood the viscosity of blood become very less .The blood pour out of blood vessels .the tissues become squeezed.Whenever a blood vessel is injured, platelets accumulate at the site of injury and help in formation of a blood clot. The clot seals the wound in the blood vessel and prevents blood loss. But if all the blood platelets are removed from blood, blood will not clot and there will be a lot of blood loss.It may even lead to the death of the person