24 Hour pH test / impedance

What is the pH test?
This test is to measure the acidity within the oesophagus and how frequently acid is moving into your gullet from your stomach. The test enables us to measure the acid levels in your oesophagus compared to the norm and to establish a link between reflux episodes and symptoms.

The 24 pH test/ impedance test is a more complete test as it also measures non acidic liquid and air, as well as the direction of travel. This test is particularly helpful for patients with atypical symptoms as it gives a far greater insight to cause of symptoms than pH testing alone.

What does the result mean?
There are a number of measures of acidity, the most common of which is the De Meester Score, which has a normal upper limit of 14.72. Anything above this is likely to be due to excess acid and a confirmation of reflux disease. Please note, however, that a normal De Meester score does not necessarily exclude reflux (though it certainly makes it less likely). If you have a high DeMeester Score and your symptoms are suggestive of acid reflux, there is a good chance that the LINX™ device could benefit you. 

What does the procedure involve?
You should not eat anything for 6-12 hours prior to the procedure although you will be able to drink water. You may also have to stop taking certain medications prior to the procedure. See medication guidance.

The test is done in the outpatient department and does not require an overnight stay in hospital. You will be asked to sit on the edge of the bed whilst a very small (2mm diameter) acid-sensitive catheter is placed in the oesophagus. The catheter is attached to a small monitoring device which fits into a carrying pouch, usually worn around the waist. Over the next 24 hours the probe will record changes in oesophageal pH and you will return the following day to have the probe removed, which takes only 5-10 minutes. All data can then be downloaded and analysed.

Testing with Bravo capsule
Another way of measuring acidity is by means of a “Bravo” capsule, which is placed in the oesophagus and avoids the need to have a tube protruding from the nose for 24-hours. However, the Bravo system is not as widely available as the standard test and the information obtained offers no obvious advantage over the normal test.  

To enquire about diagnostic testing
Call 0845 128 0053 or

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