Gastric Acid Output Test

This test assesses for low stomach acid or hypochlorhydria.

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What is the gastric acid output test?

This test measures the amount of acid produced by your stomach.

Low stomach acid or hypochlorhydria is when your stomach produces low or no acid. This can cause symptoms such as indigestion, bloating, feeling full quickly and for long periods.

How it works

A thin, flexible tube (catheter) is inserted through your nose into your stomach after an overnight fast.

A baseline measurement of 30 minutes is recorded before ingesting a nutrient drink.

Another 60 minutes of measurements are taken and the tube is removed.

Preparing for your test

Before you test, there are some things we ask you to do, to ensure safety and accurate results. This includes stopping certain medication and fasting for a short period.

Please read our patient information leaflet for full details.

For 6 hours before your test

You must stop eating and drinking and fast for 6 hours before your test.

The day of your test

  • You can have small sips of water (maximum of 300ml) until two hours before your test.

  • You may take your essential medicines with a small amount of water

  • You may brush your teeth

ⓘ If you are diabetic requiring insulin or diabetes medicine, please ask your doctor if you should change your morning dose. Oral hypoglycaemic medicines are usually not taken that morning until completion of the test and you start eating again.

Getting your test results

The results will be displayed as a graph that can be analysed by our clinical team to see how much acid your stomach is producing

Following your test, your data will be analysed and results written up into a report.

The report will be sent to both you and your referring consultant/doctor, who will explain the results to you in a follow-up consultation.

Paying for your test

Self-paying: If you are paying for this test yourself and not through insurance, the cost will be £350.

This cost includes the gastric acid output test, analysis and report.

Insurance coverage

If you have private medical insurance, most companies can cover this for you.

Got a question or want to find out more about our tests?

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