24-Hour Probe Study

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OVERVIEW PURPOSE RISKS PREPARATION DURING THE TEST AFTER THE TEST NEXT STEPS

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 low. GERD causes stomach acids to flow back into your esophagus. This can cause heartburn.

There are two ways to do a 24-hour probe study. In one way, your healthcare provider inserts a thin tube into your nose. The tube goes down into your esophagus. The tube has 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. A wire is attached to the tube in your nose. It carries data from the sensors to a portable recorder that you wear with a strap.

Once the tube is in place, you can go home. You will keep the tube in for 1 day. 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.

In the second way, the study is done with a wireless capsule that's about the size of a pencil eraser. Your healthcare provider attaches the capsule to the lining inside your esophagus. This is done with an endoscope (a flexible tube with a camera on the end). You will be sedated during this method. The capsule then sends data wirelessly to a receiver that's often attached with a strap to your wrist. The capsule falls off by itself in about 5 days and eventually passes out of the body in the stool.

Each method has different benefits. The wireless method may be more comfortable for you. There are no wires or tubes coming from your nose to the recorder. The capsule can also get data for more than 24 hours. The advantage of the tube method is that it can get other measurements, such as how well the muscles of your esophagus are working. It can also get data from many locations within the esophagus at the same time.

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 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 health 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 major 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 or capsule is inserted, or in place, you may feel:

Mild pain when swallowing
Mild pain in your throat from the tube or from the procedure to put in the tube or capsule
Pain in your chest
Pressure in your nose from the tube
A sensation of pulling or fullness when you swallow
Bleeding in the nose, throat, or esophagus from the procedure or from irritation
Infection in the nose, throat, or esophagus

With the capsule method, there are also risks from the anesthesia used during the endoscopic procedure. Talk with your healthcare provider about these risks.

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 4 to 8 hours before the test. This often means no food or drink after midnight. Ask your healthcare provider how long you should fast for your test. You may wish to shower before the test, because the recorder should not get wet.

Tell your healthcare provider if you:

Are pregnant or think you may be pregnant
Are sensitive to or allergic to any medicines, iodine, latex, tape, or anesthesia medicines (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 health condition.

What happens during a 24-hour probe study?

If you're having the tube method, 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.

If you're having the wireless capsule method, you will be sedated while the provider places the endoscope through your mouth into your esophagus. Your provider will then attach the capsule to the inside of your esophagus.

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 other levels in your esophagus.

A small recorder may be on the end of the tube that comes out of your nose. It will be joined to a strap placed over your shoulder. Or if you have the wireless capsule, you might wear a receiver on your wrist to get data from the probe.

Once the tube is in place and you are wearing the strap, you can go home. You will have to wear it for 24 hours. But you should be able to do most of your normal activities during the 24-hour probe study. If you have a wireless capsule, the study may last longer, often 48 hours.

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. It 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 pH levels in your esophagus are too low. If you have a capsule recorder, the study may last longer than 24 hours. The capsule will fall out of your esophagus in about 5 days and eventually pass in the stool.

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: