Diagnosis

Your doctor will consider your medical history, your signs and symptoms, and your test results when making a diagnosis of endocarditis. The diagnosis is usually based on several factors instead of a single positive test result or symptom.

Tests used to confirm or rule out endocarditis include:

• Blood culture test. A blood culture test is used to identify any germs in your bloodstream. Blood culture test results help your doctor choose the most appropriate antibiotic or combination of antibiotics.
• Complete blood count. This blood test can tell your doctor if you have a lot of white blood cells, which can be a sign of infection. A complete blood count can also help diagnose low levels of healthy red blood cells (anemia), which can be a sign of endocarditis. Other blood tests also may be done to help your doctor determine the diagnosis.

• Echocardiogram. An echocardiogram uses sound waves to produce images of your heart while it's beating. This test shows how your heart's chambers and valves are pumping blood through your heart. Your doctor may use two different types of echocardiograms to help diagnose endocarditis.

  In a transthoracic echocardiogram, sound waves directed at your heart from a wandlike device (transducer) held on your chest produce video images of your heart in motion. This test lets your doctor see the heart's structure and check it for any signs of damage.

  A transesophageal echocardiogram gives your doctor a closer look at your heart valves. During this test, a small transducer attached to the end of a tube is inserted down the tube leading from your mouth to your stomach (esophagus). This test provides much more detailed pictures of your heart than is possible with a transthoracic echocardiogram.

• Electrocardiogram (ECG or EKG). An ECG is used to measure the timing and duration of your heartbeats. It isn't specifically used to diagnose endocarditis, but it can show your doctor if something is affecting your heart's electrical activity. During an ECG, sensors that can detect your heart's electrical activity are attached to your chest, arms and legs.
• Chest X-ray. A chest X-ray can show your doctor the condition of your lungs and heart. It can help determine if endocarditis has caused heart swelling or if any infection has spread to your lungs.
• Computerized tomography (CT) scan or magnetic resonance imaging (MRI). You may need a CT scan or an MRI scan of your brain, chest or other parts of your body if your doctor thinks that infection has spread to these areas.