The indirect Coombs' test is done on a sample of the liquid part of the blood. It detects antibodies that are present in the bloodstream and could bind to certain red blood cells and destroy them. A Coombs' test involves taking a sample of blood.
It is placed in the middle of the chest or thoracic cavity (middle mediastinum), posterior to the body of sternum and the second to sixth costal cartilages and anterior to the fifth to the eighth thoracic vertebrae.
The human heart, which â¦ is normally about the size of your fist, is  located behind and to the left of your breastbone, also called the  sternum.Watch this animation to learn more about your heart and  how it works.he heart is about the size of your fist and is located sub-sternal, center thoracic, superior to the stomach with the apex on the left.