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 heart is located in the center of the chest, behind the sternum. In this video, Rakesh Jain, MD, an interventional cardiologist at Chippenham & Johnston-Willis Hospitals, describes both the location and size of the average human heart.he heart lies underneath the sternum, or chest bone, and sits a little to the left. The heart is located between the lungs and lies in front of the backbone. It is about the size of a fist. (This answer provided for NATA by the University of Montana Athletic Training Education Program.).