All Tests

The pericardium is a two-layered, sac-like membrane that surrounds the heart. Pericardial membranes produce pericardial fluid, a liquid that sits between the pericardium's membranes. The fluid acts as a lubricant for the movement of the heart, reducing friction as the heart pumps blood.

A variety of conditions and diseases can cause inflammation of the pericardium (pericarditis) and/or excessive accumulation of pericardial fluid (pericardial effusion). Pericardial fluid analysis is a group of tests that evaluate this liquid to help diagnose the cause of the increased fluid.

The two main reasons for fluid accumulation in the pericardial space are:

1.An imbalance between the pressure within blood vessels—which drives fluid out of blood vessels—and the amount of protein in blood—which keeps fluid in blood vessels. The fluid that accumulates in this case is called a transudate. Transudates are most often caused by congestive heart failure or cirrhosis.

2.An injury or inflammation of the pericardium, in which case the fluid that accumulates is called an exudate. Conditions such as infections, malignancies (metastatic cancer, lymphoma, mesothelioma), or autoimmune disease may cause the accumulation of exudate.

Determining if the increased fluid is transudate or exudate is important because it helps narrow down the possible causes of pericardial fluid buildup. Healthcare practitioners and laboratorians use an initial set of tests, including cell count, protein or albumin level, and appearance of the fluid, to distinguish between transudates and exudates. Once the fluid is determined to be one or the other, additional tests may be performed to further pinpoint the disease or condition causing pericarditis and/or pericardial effusion.