Your doctor will diagnose pleurisy or another pleural disorder based on your medical history, a physical exam, and test results.
                
Your doctor will want to rule out other causes of your symptoms. He or she also will want to find the underlying cause of the pleurisy or other pleural disorder so it can be treated.
                
Medical History
                
Your doctor may ask detailed questions about your medical history. He or she likely will ask you to describe any pain, especially:
                
What it feels like
                
Where it's located and whether you can feel it in your arms, jaw, or shoulders
                
When it started and whether it goes away and then comes back
                
What makes it better or worse
                
Your doctor also may ask whether you have other symptoms, such as shortness of breath, coughing, or palpitations. Palpitations are feelings that your heart is skipping a beat, fluttering, or beating too hard or fast.
                
Your doctor also may ask whether you've ever:
                
Had heart disease.
                
Smoked.
                
Traveled to places where you may have been exposed to tuberculosis.
                
Had a job that exposed you to asbestos. Asbestos is a mineral that, at one time, was widely used in many industries.
                
Your doctor also may ask about medicines you take or have taken. Reactions to some medicines can cause pleurisy or other pleural disorders. 
                
Physical Exam
                
Your doctor will listen to your breathing with a stethoscope to find out whether your lungs are making any abnormal sounds.
                
If you have pleurisy, the inflamed layers of the pleura make a rough, scratchy sound as they rub against each other when you breathe. Doctors call this a pleural friction rub. If your doctor hears the friction rub, he or she will know that you have pleurisy.
                
If you have a pleural effusion, fluid buildup in the pleural space will prevent a friction rub. But if you have a lot of fluid, your doctor may hear a dull sound when he or she taps on your chest. Or, he or she may have trouble hearing any breathing sounds.
                
Muffled or dull breathing sounds also can be a sign of a pneumothorax (a buildup of air or gas in the pleural space).
                
Diagnostic Tests
                
Depending on the results of your physical exam, your doctor may recommend tests.
                
Chest X Ray
                
Achest x rayis a painless test that creates a picture of the structures in your chest, such as your heart, lungs, and blood vessels. This test may show air or fluid in the pleural space.
                
A chest x ray also may show what's causing a pleural disorderfor example, pneumonia, a fractured rib, or a lung tumor.
                
Sometimes a chest x ray is taken while you lie on your side. This position can show fluid that didn't appear on an x ray taken while you were standing.
                
Chest CT Scan
                
A chest computed tomography (to-MOG-rah-fee) scan, orchest CT scan,is a painless test that creates precise pictures of the structures in your chest.
                
This test provides a computer-generated picture of your lungs that can show pockets of fluid. A chest CT scan also may show signs of pneumonia, a lung abscess, a tumor, or other possible causes of pleural disorders.
                
Ultrasound
                
This test uses sound waves to create pictures of your lungs. An ultrasound may show where fluid is located in your chest. The test also can show some tumors.
                
Chest MRI
                
A chest magnetic resonance imaging scan, orchest MRI,uses radio waves, magnets, and a computer to created detailed pictures of the structures in your chest. This test can show pleural effusions and tumors.
                
This test also is called a magnetic resonance (MR) scan or a nuclear magnetic resonance (NMR) scan.
                
Blood Tests
                
Blood testscan show whether you have an illness that increases your risk of pleurisy or another pleural disorder. Such illnesses include bacterial or viral infections, pneumonia, pancreatitis (an inflamed pancreas), kidney disease, or lupus.
                
Arterial Blood Gas Test
                
For this test, a blood sample is taken from an artery, usually in your wrist. The blood's oxygen and carbon dioxide levels are checked. This test shows how well your lungs are taking in oxygen.
                
Thoracentesis
                
Once your doctor knows whether fluid has built up in the pleural space and where it is, he or she can remove a sample for testing. This is done using a procedure calledthoracentesis(THOR-ah-sen-TE-sis).
                
During the procedure, your doctor inserts a thin needle or plastic tube into the pleural space and draws out the excess fluid. After the fluid is removed from your chest, it's sent for testing.
                
The risks of thoracentesissuch as pain, bleeding, and infectionusually are minor. They get better on their own, or they're easily treated. Your doctor may do a chest x ray after the procedure to check for complications.
                
Fluid Analysis
                
The fluid removed during thoracentesis is examined under a microscope. It's checked for signs of infection, cancer, or other conditions that can cause fluid or blood to build up in the pleural space.
                
Biopsy
                
Your doctor may suspect that tuberculosis or cancer has caused fluid to build up in your pleural space. If so, he or she may want to look at a small piece of the pleura under a microscope.
                
To take a tissue sample, your doctor may do one of the following procedures:
                
Insert a needle into your chest to remove a small sample of the pleura's outer layer.
                
Insert a tube with a light on the end (endoscope) into tiny cuts in your chest wall so that he or she can see the pleura. Your doctor can then snip out small pieces of tissue. This procedure must be done in a hospital. You'll be given medicine to make you sleep during the procedure.
                
Snip out a sample of the pleura through a small cut in your chest wall. This is called an open pleural biopsy. It's usually done if the sample from the needle biopsy is too small for an accurate diagnosis. This procedure must be done in a hospital. You'll be given medicine to make you sleep during the procedure.