Appendicitis Tests
Reviewed
Also called: Appendicitis Test, Appendix Tests, Appendicitis Diagnostic Tests, Appendicitis Blood and Imaging Tests
Appendicitis tests are used to diagnose appendicitis, an inflammation (swelling) or infection of your appendix.
Specimen: Blood (serum or plasma), urine (clean catch), or none (for imaging tests)
Urgent safety information
If you have any severe abdominal pain, it's important to get medical help as soon as possible. This is because severe abdominal pain can be a sign that your appendix may burst.
Why this test may be ordered
- To evaluate abdominal pain that may be from appendicitis
- To find signs of infection or inflammation
- To rule out other conditions that mimic appendicitis (e.g., urinary tract infection, kidney stones, ectopic pregnancy)
- To confirm or rule out appendicitis with imaging
Preparation and collection
Blood and urine tests don't require any special preparations. For imaging tests, you may have to stop eating and drinking for several hours before the test. Your provider will tell you how to prepare.
Before ordering appendicitis tests, your provider will ask questions about your symptoms and medical history. They will then likely start with a physical exam. During a physical exam, your provider will press on the right side of your abdomen to see if you feel any pain. If your provider thinks you could have appendicitis, they may order one or more tests to help confirm or rule out the diagnosis. These include blood tests, urine tests, and imaging tests.
A blood test has very little risk. You may have slight pain or bruising at the spot where the needle was put in, but it usually goes away quickly. A urine test has no risk. If your test includes contrast dye, there's a small chance you could have an allergic reaction to it. But exposure to radiation can slightly increase the risk of developing cancer later in life. Radiation can especially affect children and fetuses because their bodies are still growing. If you're concerned about radiation exposure for yourself, your fetus, or your child, ask about other imaging tests to diagnose appendicitis.
Understanding results
If a result or symptoms suggest an emergency, get emergency medical help right away.
To confirm or rule out appendicitis, your provider will consider your symptoms, medical history, and the results of your exam and appendicitis tests.
- High white blood cell count or high C-reactive protein (CRP) level: A high white blood cell count means you probably have an infection. A high level of c-reactive protein (CRP) in your blood means that you have inflammation in your body that could be from appendicitis. Limitation: But this test alone can't diagnose appendicitis. Next step: If your symptoms and other tests suggest that you have appendicitis, imaging tests can confirm the diagnosis.
- Normal blood test results: It's also possible to have appendicitis with a normal white blood cell count. Limitation: But blood tests can't show whether appendicitis is the cause. Next step: To confirm or rule out appendicitis, your provider will consider your symptoms, medical history, and the results of your exam and appendicitis tests.
- Imaging shows an appendix that is blocked, larger than normal, burst, or has an abscess: An appendix that is blocked, larger than normal, burst, or has an abscess means that you probably have appendicitis. Limitation: Because appendicitis can be difficult to diagnose, your health care provider may use a range of tests. Next step: If your appendix has already burst, you must have surgery right away. The surgeon will remove your appendix and clean the infection from your abdomen.
- Imaging shows a normal appendix: If your appendix looks normal, imaging tests may help find other problems that could be causing abdominal pain. Limitation: Because appendicitis can be difficult to diagnose, your health care provider may use a range of tests. Next step: To confirm or rule out appendicitis, your provider will consider your symptoms, medical history, and the results of your exam and appendicitis tests.
- Blood tests cannot diagnose appendicitis; they only indicate infection or inflammation. A normal white blood cell count does not rule out appendicitis.
- Urine tests cannot diagnose appendicitis; they help find other causes of symptoms, such as urinary tract infections or kidney stones.
- CT scans use radiation which slightly increases lifetime cancer risk; children and unborn babies are more sensitive. Contrast dye may cause allergic reactions.
- If you have certain metals or implanted medical devices, MRI may not be safe.
What to do next
If your provider diagnoses appendicitis, you'll usually have surgery to remove your appendix as soon as possible before it can burst. If your appendix has already burst, you must have surgery right away.
- What do my test results show about my appendix?
- Could something other than appendicitis be causing my pain?
- Is a CT scan safe for me if I am or could be pregnant?
- Do I need surgery, and how soon?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.