24-Hour Probe Study

What is a 24-hour probe study?

The 24-hour probe study measures the pH (acid level) in your food pipe (esophagus). It is often done along with the monitoring of nonacid and air regurgitation in a 24-hour pH/impedance probe study.

Your esophagus is the tube that goes from your mouth to your stomach. If you have gastroesophageal reflux disease (GERD), the pH levels in your esophagus can be too high. GERD causes stomach acids to flow back into your esophagus. This can cause heartburn.

For the 24-hour probe study, your healthcare provider will insert a thin tube into your nose. The tube goes down into your esophagus. The tube will have multiple sensors on it. The sensors read your pH levels and the location of both air and liquid in your esophagus as it flows up from your stomach.

Once the tube is in place, you can go home. You will keep the tube in for 1 day. But you will be able to do most of your normal activities while you have the tube in place.

After 24 hours, your healthcare provider will remove the tube and sensors. Your healthcare provider will check the information to see if you have GERD.

Why might I need a 24-hour probe study?

The 24-hour probe study is used to see if you have GERD. It may also be used to see if your GERD treatment is helping to reduce your stomach acid level.

If GERD isn’t treated, the acids can hurt the tissues of your esophagus. This can lead to more health problems, such as Barrett's esophagus. That is when abnormal tissues grow and take over normal esophagus tissue.

The 24-hour probe study can help stop such problems. It can tell if you have any medical problems. It can also make sure the care you are getting is working.

What are the risks of a 24-hour probe study?

The 24-hour probe study has no real risks. There are only a few small side effects. It may not feel very good when your healthcare provider inserts the tube and when you wear it. When the tube is inserted, you may feel:

  • Mild pain when swallowing
  • Mild pain in your throat
  • Pain in your chest
  • Pressure in your nose
  • A pulling sensation when you swallow

How do I get ready for a 24-hour probe study?

Your healthcare provider will explain how the 24-hour probe study is done. Be sure to ask any questions you may have.

You will be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if something is not clear.

Tell your healthcare provider about all the medicines you take. This includes over-the-counter medicines such as ibuprofen. It also includes vitamins, herbs, and other supplements.

You must not eat or drink anything for 8 hours before the test. This often means no food or drink after midnight. You may wish to shower before the test, because the monitor should not get wet.

Tell your healthcare provider if you:

  • Are pregnant or think you may be pregnant
  • Are sensitive to or are allergic to any medicines, iodine, latex, tape, or anesthesia drugs (local and general)
  • Have a history of bleeding disorders or are taking any blood-thinning (anticoagulant) medicines, aspirin, or other medicines that affect blood clotting. You may have to stop taking these medicines before your procedure.

Your healthcare provider may have other instructions for you based on your medical condition.

What happens during a 24-hour probe study?

The inside of your nose will be numbed. This will make you more comfortable as the tube and sensor are inserted. Your healthcare provider will then put the tube (with multiple sensors on it) into your nose. They will push the tube down your throat while you swallow.

The sensor will stay just above the lower esophageal sphincter (LES). The LES is the muscle that keeps stomach acids out and lets food into your stomach. The LES is at the bottom of your esophagus. You may have other sensors too. They may check the pH levels in your stomach and esophagus.

A small recorder will be on the end of the tube that comes out of your nose. It will be joined to a strap placed over your shoulder.

Once the tube is in place and you are wearing the strap, you can go home. You will have to wear this for 24 hours. But you should be able to do most of your normal activities during the 24-hour probe study.

Your healthcare provider will likely have you keep a diary. You should list all the foods you eat and when you eat them. You should also list when you sleep and any symptoms you have. Follow your provider's instructions very closely. This will help you get the most exact results.

What happens after a 24-hour probe study?

After 24 hours, you will go back to your healthcare provider. They will take out the tube and any sensors. Your healthcare provider will check the results and compare them with your diary. They will score the results. The results will show if acid levels in your esophagus are too high.

Your healthcare provider will discuss the results with you. Then you will make a plan of care together. This may include changes to the plan you already have.

Your new care plan will:

  • Help lower your stomach acid level
  • Keep your symptoms under control
  • Stop stomach acid from hurting your esophagus

Next steps

Before you agree to the test or the procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person’s qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
  • Who to call after the test or procedure if you have questions or problems
  • How much will you have to pay for the test or procedure
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