What does pericardiocentesis show?

The cause of fluid: The fluid which has built up around the heart is removed. Examining the appearance grossly and under the microscope of that fluid and culturing it will lead to diagnosing why it formed in the first place. It could show infection, tumor cells, inflammation, or point to a hypoactive thyroid as the reason for the fluid collection.

Fluid: The pericardium is the sac around the heart. It has a small amount of normal clear fluid. If there is more fluid, then one needs to find the cause. Blood heart failure renal failure pus can be identified with the "centesis" is drawing the sample of fluid.