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 chest cavity. It is surrounded by a covering called the pericardium. The heart itself is divided into four chambers, called the right and left atria and the right and left ventricles. The heart is connected to the rest of the body by means of VEINS which return to the lungs and the ARTERIES which pump blood to the body.