A newborn baby has approximately 1 cup of blood in its entire body. The average adult has between 10 and 12 pints of blood in their body .Human blood is made up of red blood cells, white blood cells, Platelets, plasma and cryoprecipitate. A person’s blood makes up 7 percent of the body’s weight. A newborn baby receives a blood test to find out blood type for the child. This is usually done during the first visit to the pediatrician. The blood-type test is commonly called the heel stick test because the person taking blood from the newborn child pricks the heel of the child to get the blood.