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 a hollow, muscular organ located between the lungs and underneath the breastbone. A muscular wall divides the heart into two sides â the right side and the left side. Each side has two chambers. The two upper chambers of the heart are called the atria. The atria are the filling chambers.