Pericardial fluid that is obtained from the heart is stained with a violet stain known as gram stain. The sample is then examined under the microscope for the presence of bacteria. The color, number, and morphologic appearance of the cells help make it possible to identify the organism. The test is performed when an infection of the heart is suspected, or when a pericardial effusion is present.
Review Date 12/1/2018
Updated by: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.