Pleural Fluid Analysis
A pleural fluid analysis is a group of tests that examine a sample of abnormal fluid that builds up in the space between your lungs and chest wall.
A pleural fluid analysis is a group of tests that examine a sample of abnormal fluid that builds up in the space between your lungs and chest wall. This space is called the pleural space. The pleura is a thin tissue that covers the outside of your lungs and lines the inside wall of your chest. Normally, a small amount of fluid, called pleural fluid, fills the space between the two layers of pleural tissue. This fluid keeps the pleura moist and helps the layers of tissue glide smoothly over each other as you breathe. If too much fluid builds up in your pleural space, it's called a pleural effusion . Many different types of conditions can cause pleural effusion. The fluid buildup doesn't always cause symptoms, but if it presses on your lungs, you may have trouble breathing , even if your lungs are healthy. A pleural fluid analysis can help find the cause of a pleural effusion. Treating the cause may help keep the fluid from building up in the future. The fluid buildup you have now usually needs treatment, too. Without treatment, it may lead to a collapsed lung and other serious health problems. Other names: pleural fluid aspiration, diagnostic thoracentesis, pleural fluid tap, pleural fluid culture, pleural fluid cytology, pleural effusion testing, LDH body fluid
Why is this test ordered? You may need this test if you have symptoms of pleural effusion and an imaging test , such as an MRI scan or chest x-ray , shows that you have fluid buildup around your lungs. The symptoms of pleural effusion depend on the cause and the amount of fluid. They may include: Chest pain that doesn't have another explanation Dry cough that doesn't bring up mucus Trouble breathing Fatigue If the cause of your pleural effusion is known, you may not need a pleural fluid analysis even if you have symptoms. Pleural effusions don't always cause symptoms, so sometimes a pleural effusion is found on a chest imaging test that's done for another reason. If this happens, a pleural fluid test is often done, even though you don't have symptoms.
Clinical Interpretation
A pleural fluid analysis usually includes results from several tests done on your fluid sample. Your provider will consider all your test results, your symptoms, and your medical history to understand what your results mean. Ask your provider to explain what your test results say about your health. In general, the results of your pleural fluid analysis will show which type of fluid is in your pleural space. There are two main types of fluid, and each type has different possible causes. To find out which type of fluid you have, your test usually uses a set of guidelines called Light's criteria. Light's criteria tell providers how to compare the amount of certain proteins in your pleural fluid to the amount of those proteins measured in your blood. The results of the comparison will show whether your pleural fluid is transudate or exudate: Transudate is a watery fluid that has low amounts of protein. It's caused by pressure in your blood vessels. The pressure makes fluid leak from your blood vessels into the pleural space. Transudate fluid is most often caused by: Heart failure Kidney disease Liver disease , including cirrhosis Exudate is a cloudy fluid that has high amounts of protein. It can be caused by conditions that involve inflammation, infections, and other conditions that affect blood vessels or lymphatic vessels , which are part of your immune system. These conditions include: Pancreatitis Certain autoimmune diseases , including rheumatoid arthritis and lupus Cancer , most often leukemia , lymphoma , breast or lung cancer Lung diseases that aren't cancer, including infections, such as pneumonia or tuberculosis Lung or chest injuries Exudate contains different substances depending on the condition that caused it. For example, exudate from an infection may have signs of pus, bacteria, or fungus . Exudate from cancer usually has cancer cells. A chest injury may cause exudate that includes blood. To help find the specific cause of your pleural effusion, your provider will order other tests on your fluid sample to check for certain substances. The tests you have will depend on the most likely causes of your pleural effusion, based on all the information about your condition. In certain cases, you may also need other types of tests, including blood and/or urine tests, imaging tests, a bronchoscopy , or a biopsy . If you have questions about your test results, talk with your provider. Learn more about laboratory tests, reference ranges, and understanding resu lts.
Clinical Protocol & Patient Advice
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In general, a thoracentesis doesn't require special preparations. Your provider will let you know if there's anything you need to do or avoid doing. For example, you may need to stop taking certain medicines before your test. But never stop taking any prescription medicines without talking with your provider first. or a blood test.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.