URL of this page: https://medlineplus.gov/lab-tests/appendicitis-tests/

Appendicitis Tests

What are appendicitis tests?

Appendicitis is an inflammation or infection of the appendix. The appendix is a small pouch attached to the large intestine. It's located in the lower right side of your abdomen. The appendix has no known function, but appendicitis can cause serious health problems if not treated.

Appendicitis happens when there is some kind of blockage in the appendix. A blockage can be caused by stool, a parasite, or other foreign substance. When the appendix is blocked, bacteria build up inside it, leading to pain, swelling, and infection. If not treated promptly, the appendix can burst, spreading infection throughout your body. A burst appendix is a serious, sometimes life-threatening condition.

Appendicitis is very common, mostly affecting teens and adults in their early twenties, but it can happen at any age. Appendicitis tests help diagnose the condition, so it can be treated before the appendix bursts. The main treatment for appendicitis is surgical removal of the appendix.

What are they used for?

The tests are used for people with appendicitis symptoms. They can help diagnose appendicitis before it causes serious complications.

Why do I need appendicitis testing?

You may need testing if you have symptoms of appendicitis. The most common symptom is pain in the abdomen. The pain often starts by your belly button and shifts to your lower right abdomen. Other appendicitis symptoms include:

What happens during appendicitis testing?

Appendicitis tests usually include a physical exam of your abdomen and one or more of the following:

  • Blood test to check for signs of infection. A high white blood cell count is a sign of an infection, including, but not limited to, appendicitis.
  • Urine test to rule out a urinary tract infection.
  • Imaging tests, such as an abdominal ultrasound or CT scan, to view the inside of your abdomen. Imaging tests are often used to help confirm a diagnosis, if a physical exam and/or blood test show possible appendicitis.

During a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a urine test,  you will need to provide a sample of your urine. The test may include the following steps:

  • Wash your hands.
  • Clean your genital area with a cleansing pad given to you by your provider. Men should wipe the tip of their penis. Women should open their labia and clean from front to back.
  • Start to urinate into the toilet.
  • Move the collection container under your urine stream.
  • Collect at least an ounce or two of urine into the container, which should have markings to indicate the amounts.
  • Finish urinating into the toilet.
  • Return the sample container as instructed by your health care provider.

An abdominal ultrasound uses sound waves to view the inside of your abdomen. During the procedure:

  • You will lie on an exam table.
  • A special gel will be placed on your skin over the abdomen.
  • A handheld probe called a transducer will be moved over the abdomen.

A CT scan uses a computer that's linked to an x-ray machine to create a series of pictures of the inside of your body. Before the scan, you may need to take in a substance called contrast dye. Contrast dye helps the images show up better in the x-ray. You may get contrast dye through an intravenous line or by drinking it.

During the scan:

  • You will lie on a table that slides into the CT scanner.
  • The scanner's beam will rotate around you as it takes pictures.
  • The scanner will take pictures at different angles to create three-dimensional images of your appendix.

Will I need to do anything to prepare for the tests?

You don't need any special preparations for a blood or urine test.

For an abdominal ultrasound or CT scan, you may be asked to not eat or drink for several hours before the procedure. If you have questions about how to prepare for your test, talk to your health care provider.

Are there any risks to the tests?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

There is no risk to having a urine test.

An ultrasound may feel a bit uncomfortable, but there is no risk.

If you've taken contrast dye for a CT scan, it may taste chalky or metallic. If you got it through an IV, you may feel a slight burning sensation. The dye is safe in most cases, but some people may have an allergic reaction to it.

What do the results mean?

If your urine test is positive, it may mean you have a urinary tract infection instead of appendicitis.

If you have appendicitis symptoms and your blood test shows a high white cell count, your provider may order an abdominal ultrasound and/or a CT scan to help confirm a diagnosis.

If appendicitis is confirmed, you will have surgery to remove the appendix. You may get this surgery, called an appendectomy, as soon as you are diagnosed.

Most people recover very quickly if the appendix is removed before it bursts. If surgery is done after the appendix bursts, recovery may take longer and you may have to spend more time in the hospital. After surgery, you will take antibiotics to help prevent infection. You may need to take the antibiotics for a longer time if your appendix burst before surgery.

You can live a completely normal life without an appendix.

Is there anything else I need to know about appendicitis testing?

Sometimes the tests misdiagnose appendicitis. During surgery, the surgeon may find that your appendix is normal. He or she may remove it anyway to prevent appendicitis in the future. Your surgeon may continue to look in the abdomen to find the cause of your symptoms. He or she may even be able to treat the problem at the same time. But you may need more tests and procedures before a diagnosis can be made.

References

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  2. Cleveland Clinic [Internet]. Cleveland (OH): Cleveland Clinic; c2018. Appendicitis: Overview [cited 2018 Dec 5]; [about 3 screens]. Available from: https://my.clevelandclinic.org/health/diseases/8095-appendicitis
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  10. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Blood Tests [cited 2018 Dec 5]; [about 3 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests
  11. National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Definition and Facts for Appendicitis; 2014 Nov [cited 2018 Dec 5]; [about 4 screens]. Available from: https://www.niddk.nih.gov/health-information/digestive-diseases/appendicitis/definition-facts
  12. National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Symptoms and Causes of Appendicitis; 2014 Nov [cited 2018 Dec 5]; [about 4 screens]. Available from: https://www.niddk.nih.gov/health-information/digestive-diseases/appendicitis/symptoms-causes
  13. National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Treatment for Appendicitis; 2014 Nov [cited 2018 Dec 5]; [about 4 screens]. Available from: https://www.niddk.nih.gov/health-information/digestive-diseases/appendicitis/treatment
  14. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Abdominal CT scan: Overview [updated 2018 Dec 5; cited 2018 Dec 5]; [about 2 screens]. Available from: https://ufhealth.org/abdominal-ct-scan
  15. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Abdominal ultrasound: Overview [updated 2018 Dec 5; cited 2018 Dec 5]; [about 2 screens]. Available from: https://ufhealth.org/abdominal-ultrasound
  16. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Appendicitis: Overview [updated 2018 Dec 5; cited 2018 Dec 5]; [about 2 screens]. Available from: https://ufhealth.org/appendicitis
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The medical information provided is for informational purposes only, and is not to be used as a substitute for professional medical advice, diagnosis or treatment. Please contact your health care provider with questions you may have regarding medical conditions or the interpretation of test results.

In the event of a medical emergency, call 911 immediately.