This is a method of staining microorganisms (bacteria) using a special series of stains. In this test, a specimen of pericardial fluid (fluid in the sac surrounding the heart) is stained and then examined under the microscope.

The fluid must first be obtained from the sac surrounding the heart. In some people, a cardiac monitor may be placed prior to the test to monitor for heart disturbances. Patches called electrodes will be placed on the chest similar to an ECG. A chest X-ray or ultrasound may precede the test.

The skin of the chest will be cleansed with antibacterial soap. A trained physician, often a cardiologist, will obtain the sample. A small needle is inserted into the chest between the ribs into the pericardium, the thin sac that surrounds the heart, and a small amount of fluid is withdrawn. There will be a sensation of pressure and some pain as the needle is inserted into the chest.

An ECG and chest X-ray may also follow the procedure. Sometimes the pericardial fluid is obtained during open heart surgery.

A drop of the pericardial fluid is then applied in a very thin layer to a microscope slide -- this is called a smear. The specimen is stained with a series of stains, together called a Gram stain. It is first stained with crystal violet stain, then iodine, then decolorized, then stained with safranin. The stained smear is then examined under the microscope for the presence of bacteria.

The color, size, and morphologic appearance (shape) of the cells help make it possible to identify the infecting organism.

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)