Acute Respiratory Distress Syndrome Diagnosis

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Your doctor will diagnose acute respiratory distress syndrome (ARDS) based on your medical history, a physical exam, and test results. ARDS can be difficult to diagnose and is often mistaken for another condition, so it is important to know your symptoms.

To help diagnose ARDS, your doctor may ask you about any medical conditions or recent events that could be considered risk factors. For example, traveling could be a risk factor because of potential exposure to infections that are more common in certain geographic areas.

Your doctor will also ask about your symptoms and whether you have a heart problem, such as heart failure, or another condition that can cause symptoms similar to those for ARDS.

Your doctor will examine you for signs of ARDS. This exam may include:

• Listening to your lungs through a stethoscope for abnormal breathing sounds, such as crackling
• Listening to your heart for a fast heart rate
• Checking for signs that you are having difficulty breathing, such as using muscles in your chest to help you breathe
• Examining your skin or lips for a bluish tone, which can signal a low blood oxygen level
• Examining your body for swelling or other signs of extra fluid, which may be linked to heart or kidney problems
• Measuring your blood pressure and oxygen levels

To diagnose ARDS, your doctor may have you undergo some of the following tests and procedures. Different tests may be appropriate for different ages and can include:

• Blood tests measure the oxygen level in your blood, using a sample of blood taken from an artery. A low blood oxygen level might be a sign of ARDS. To confirm the cause of your symptoms, your doctor may also check your blood for signs of infection or a heart problem, or to see how well other organs are working.
• Other tests of blood oxygen levels, such as pulse oximetry, that do not require collecting a blood sample may be done. For these tests, a sensor is attached to the skin or placed on a hand or foot.
• Lung imaging tests, such as a chest X-ray or computerized tomography (CT) scan, create detailed images of your lungs.
• Lung biopsy may be done if other tests do not confirm a diagnosis.

Other tests, such as the following, can help find the cause of your ARDS or determine whether there is another type of problem:

• A sputum culture can help find the cause of an infection. The culture is used to study the phlegm you have coughed up from your lungs.
• Bronchoscopy can diagnose a lung problem when there is no clear cause of your ARDS. As part of this test, your doctor may rinse an area of your lung to get cells and examine them under a microscope or with other tests.
• Urine tests detect bacterial infections or rule out kidney problems.