An enlarged spleen is usually detected during a physical exam. Your doctor can often feel the enlargement by gently examining your left upper abdomen, just under your rib cage. However, in some people especially those who are slender a healthy, normal-sized spleen can sometimes be felt during an exam.
Your doctor may confirm the diagnosis of an enlarged spleen with one or more of these tests:
- Blood tests, such as a complete blood count to check the number of red blood cells, white blood cells and platelets in your system
- Ultrasound or computerized tomography (CT) scan to help determine the size of your spleen and whether it's crowding other organs
- Magnetic resonance imagining (MRI) to trace blood flow through the spleen
Imaging tests aren't always needed to diagnose an enlarged spleen. But if your doctor recommends imaging, you generally don't need any special preparation for an ultrasound or MRI. If you're having a CT scan, however, you may need to refrain from eating before the test. If you need to prepare, your doctor will let you know well in advance.
Finding the cause
Sometimes you may need further testing to identify what's causing an enlarged spleen, including liver function tests and a bone marrow exam, which can give more detailed information about your blood cells than can blood drawn from a vein.
In some cases, a sample of solid bone marrow is removed in a procedure called a bone marrow biopsy. Or you may have a bone marrow aspiration, which removes the liquid portion of your marrow. In many cases, both procedures are performed at the same time (bone marrow exam).
Both the liquid and solid bone marrow samples are frequently taken from the same place on the back of one of your hipbones. A needle is inserted into the bone through an incision. Because bone marrow tests cause discomfort, you'll receive either general or local anesthesia before the test.
Because of the risk of bleeding, a needle biopsy of the spleen is almost never done.
Occasionally, when there's no explanation for an enlarged spleen despite a thorough investigation for a cause, your doctor may recommend surgery to remove your spleen. After surgical removal, the spleen is examined under a microscope to check for possible lymphoma of the spleen.