This article was last reviewed on
This article waslast modified on 24 July 2019.
At a Glance
Why Get Tested?

To help diagnose the cause of inflammation of the pericardium and/or fluid accumulation around the heart

When To Get Tested?

When a doctor suspects that someone has a condition associated with inflammation of the pericardium and/or fluid accumulation around the heart

Sample Required?

A sample of fluid is collected from the pericardial sac by a doctor with a syringe and needle using a procedure called a pericardiocentesis

Test Preparation Needed?

None

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Pericardial fluid is a liquid that acts as a lubricant for the movement of the heart. It is found in small quantities between the two layers of the pericardium. Pericardial fluid is produced by mesothelial cells in the membranes and reduces 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 used to help find the cause of the problem. There are two main reasons why fluid may collect in the pericardial space:

  • Fluid may accumulate because of 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 of the liver. If the fluid is determined to be a transudate, then usually no more tests on the fluid are necessary.
  • Fluid accumulation may be caused by injury or inflammation of the pericardium, in which case the fluid is called an exudate. This type of fluid may be the result of conditions such as infection (like tuberculosis), cancer (metastatic cancer, lymphoma, mesothelioma), rheumatoid disease, or systemic lupus erythematosus.

It is important to distinguish between the two types of fluid because it helps diagnose the disease or condition. Doctors use an initial set of tests (cell count, protein or albumin and appearance of the fluid) to distinguish between transudates and exudates. Once the sort of fluid has been identified, additional tests may be done to help pinpoint the disease or condition causing pericarditis and/or pericardial effusion.

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Common Questions
  • How is it used?

    Pericardial fluid analysis is used to help diagnose the cause of inflammation of the pericardium (pericarditis) and/or fluid accumulation around the heart (pericardial effusion). An initial set of tests (protein or albumin, cell count and appearance) is used to differentiate between the two types of fluid that may be produced (transudate and exudate). Additional tests on the fluid itself may be used to help distinguish possible conditions causing an exudate:

  • When is it requested?

    Pericardial fluid analysis may be requested when a doctor suspects that a patient has a condition or disease that is causing pericarditis and/or pericardial effusion. It may be used when a patient has some combination of the following signs and symptoms:

    • Chest pain, sharp or sometimes dull, that may be relieved by bending forward
    • Coughing
    • Difficulty breathing or shortness of breath
    • Discomfort when breathing while laying down
    • Chest fullness
    • Fever
    • Fatigue
    • Changes in heart rhythm
    • Enlarged heart size on chest X-ray
    • Abnormal pericardial appearance on echocardiogram
  • What does the test result mean?

    An initial set of tests performed on a sample of pericardial fluid helps determine whether the fluid is a transudate or exudate.

    Transudate:

    • Physical characteristics—fluid appears clear
    • Protein or albumin level—decreased
    • Cell count—few cells are counted

    Transudates usually require no further testing. They are most often caused by either cirrhosis or congestive heart failure.

    Exudate:

    • Physical characteristics—fluid may appear cloudy
    • Protein or albumin level—higher than normal
    • Cell count—increased

    Exudates can be caused by a variety of conditions and diseases and usually require further testing to aid diagnosis. Exudates may be caused by, for example, infections, trauma, various cancers, or pancreatitis. The following is a list of additional tests that the doctor may order depending on the suspected cause:

    Physical characteristics – the normal appearance of a sample of pericardial fluid is straw coloured and clear. Abnormal results may give clues to the conditions or diseases present:

    • Milky appearance—may point to lymphatic system involvement
    • Reddish pericardial fluid may indicate the presence of blood
    • Cloudy thick pericardial fluid may indicate the presence of microorganisms and/or white blood cells

    Chemical tests –in addition to protein or albumin, a glucose test may be performed. Glucose in pericardial fluid samples is typically about the same as blood glucose levels. It may be lower with infection.

    Microscopic examination – Normal pericardial fluid has small numbers of white blood cells (WBCs) but no red blood cells (RBCs) or microorganisms. Laboratories may examine drops of the pericardial fluid and/or use a special centrifuge (cytocentrifuge) to concentrate the fluid’s cells at the bottom of a test tube. Samples are placed on a slide, treated with special stain, and an evaluation of the different kinds of cells present is performed.

    • Total cell counts—quantity of WBCs and RBCs in the sample. Increased WBCs may be seen with infections and other causes of pericarditis.
    • WBC differential—determination of percentages of different types of WBCs. An increased number of neutrophils may be seen with bacterial infections.
    • Cytology – a cytocentrifuged sample is treated with a special stain and examined under a microscope for abnormal cells. This may be done when a mesothelioma or metastatic cancer is suspected. The presence of certain abnormal cells, such as tumour cells or immature blood cells, can indicate what type of cancer is involved.

    Infectious disease tests – routine tests may be performed to look for microorganisms if infection is suspected:

    • Gram stain - for direct observation of bacteria or fungi under a microscope. There should be no organisms present in pericardial fluid.
    • Bacterial culture and susceptibility testing - used to detect any microorganisms, which will grow in the culture. If bacteria are present, susceptibility testing can be performed to guide antimicrobial therapy. If there are no microorganisms present, it does not rule out an infection; they may be present in small numbers or their growth may be inhibited because of prior antibiotic therapy.
    • Adenosine Deaminase - rarely, this test may be used to help detect tuberculosis. If the level is markedly elevated in pericardial fluid in a person with symptoms suggesting tuberculosis, makes it likely that the person has Mycobacterium tuberculosis infection in the pericardiam.

    Other tests for infectious diseases that are less commonly ordered may include tests for viruses, mycobacteria (AFB smear and culture), and parasites.

  • Is there anything else I should know?

    Increased amounts of pericardial fluid also can restrict the movement of the heart. Cardiac tamponade is when pericardial fluid builds up to the point that pressure on the heart prevents it from filling normally. Rapid fluid build-up can be a medical emergency, causing heart failure and death. When fluid accumulates slowly, the pericardial sac stretches and symptoms gradually worsen.

    A blood glucose, protein, or albumin  may be requested to compare concentrations with those in the pericardial fluid.

  • What is pericardiocentesis and how is it performed?

    Pericardiocentesis is the removal of pericardial fluid from the pericardial sac with a needle and syringe. An intravenous (IV) line may be started and the person may be given medications prior to the sample collection. The patient is positioned lying down. A local anaesthetic is applied, then the doctor inserts the needle into the space between the ribs (fifth to sixth intercostals space) on the left side of the chest and into the pericardial sac and removes a fluid sample. An ultrasound scan may be used to help guide the needle.

  • Are there other reasons to do a pericardiocentesis?

    Yes. Sometimes it will be performed to drain excess pericardial fluid – to relieve pressure on the heart and/or to aid in the treatment of an infection. Sometimes a catheter drain is left in place for a period of time to remove larger amounts of fluid and to drain recurrent fluid accumulations. Sometimes medications will be introduced into the space during the pericardiocentesis.

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