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.
Confidence votes 30.4K. The heart is located under the rib cage between the lungs, with slightly more to the left of midline than the right. The human heart, which 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. right behind your ribcage & a little to the left in the center of your body.