The thought of stomach acid testing procedures can be a daunting thought for some. Particularly once you learn how a stomach acid test is typically completed.
The best results with regard to the reliability and accuracy of a test are obtained through seeing a specialist. As much as this might sound like it is a bit over the top, it all depends on what you really want to achieve.
There are alternatives to seeing a Specialist, such as home testing kits and a curious DIY method involving baking soda. However, the accuracy and reliability of these are understandably debatable.
When it comes to information to base a diagnosis on, the more honest and complete empirical data the better. Hence, we won’t be diving in to exploring the DIY baking soda method here.
What is a Stomach Acid Test?
The stomach acid test we will look at in more detail below is considered to be a non-invasive way of measuring the acidity level in your stomach. What is being measured here is expressed as the pH level.
What the heck is pH? It is short for the ‘potential of hydrogen’ and as a trusted methodology for almost 100 years, it looks at logarithmic expression of acidity or alkalinity.
Invested by Søren Peter Lauritz Sørensen when he was reportedly experimenting with beer, this scale has long served people all over the world in a very wide range of applications. 
A stomach acid test is done after you have not eaten for typically between 2 and 6 hours at a minimum. This way there’s only fluid left in your stomach. This allows for an accurate pH recording to be taken.
What happens During a Stomach Acid Test?
Acid sample readings from your stomach are typically obtained through a small tube that is guided down into your esophagus, or if required, your stomach.
This device measures esophageal impedance pH, normally over a 24 hour period.
The process is one that some people describe as uncomfortable or distressing, even when performed by a professional medical practitioner. Hence, attempting to self-administer any process of the sort is not advisable.
Trigger Warning: the below videos show the insertion of various probes, and can be distressing for some to observe.
In the video below you will see how this is inserted through the nose, and the obvious discomfort experienced by someone who clearly knows how these work.
Further explanation of how reflux is able to be measured in the esophagus is covered in the video below. Notice how shallow the probe is inserted in the and how much the young boy struggles with this.
Remember, looking after yourself is a form of prevention. My Grandmother always said that prevention is much better than cure. If you can avoid needing to go through experiences like this, all the better.
This next video is one which I feel requires a particular trigger warning! It shows the camera footage captured inside the throat as the probe is fed down into the esophagus through the nose.
I do feel that the patient’s responses at the end of the procedure are very scripted, which makes her account of the process feel less genuine to me.
Where a probe is required to be fed all the way down to your stomach, this is typically done with what is called an aspiration tube. A hormone known as gastrin may also be injected to test the cells of the stomach. in some cases it is necessary for the stomach contents are removed and analysed. [2, 3]
Less Invasive Testing Methods
Acid levels in the stomach are able to be reasonably measured thought a mouth swab. One such method that is available is called a Peptest.
The mouth swab test involves collecting samples of your saliva, breath, or stomach acid. After the collection process, a spit test is performed and if a strong enough quantity of stomach acid is detected, then you are considered acid resistant.
The spit test is essential for a doctor to use for the stomach acid test to be 100% accurate.
Please note, we have no affiliation with the manufacturer of the Peptest product, or any other products referenced here, and do not share their products with you here as any means of endorsement.
This is mentioned simply as a means to illustrate options and contrast between methodologies and technologies for collecting data which are considerably less challenging to undergo than a 24 hour esophageal impedance pH test.
Where samples are taken from the stomach, a small amount of stomach acid is placed on the surface of a test strip. The function of these test strips is a lot like a soil pH testing kit.
The test strips respond to the material they come into contact with and change colour to give an indication of the pH.
How to Prepare for a Test
Often there is a requirement to present for a test after a small window of fasting.
Before you go for the test, it is helpful to know what food and drink to avoid and what you should eat or drink. Just as important, knowing what you have consumed recently, and even having a food diary to refer to will help provide information to help with the data analysis.
You may find that depending on the type of test you are advised is necessary that there are different preparation requirements.
An esophageal impedance pH test will require you to eat and drink as you normally do, with certain considerations given to the data to be collected through foods or drinks that are aggravators. 
What are the Risks using a Probe for Testing?
- Probe misdirection
The probe may be directed down the throat and into the lungs instead of the esophagus. Depending upon how deep and forceful the insertion, damage or injury to the lungs may occur. As a result, tearing, or perforation of the lungs is possible.
Probes may also be fed down too far into the stomach resulting in similar complications. Internal bleeding as a result is possible.
- Reactions to sedatives
Where sedatives (anesthetics) are used, these can cause different people to react in different ways. It is important to advise your Doctor or Specialist of known issues before any sedatives are administered. Reactions may include showing signs such as:
- Problems with breathing
- Notable changes in heart rate and blood pressure
In closing, as with all content provided on our website, this by no means is intended to be considered medical advice. This information is provided for education purposes only.
We are not Doctors and do not have the ability to provide medical advice. It is your responsibility to seek out a trusted professional to assist you with any conditions or concerns you may have. We are not in a position to do so.
Stomach acid testing procedures like those described in this article are arguably avoidable when prevention through a healthy diet and lifestyle are given priority.
- “S. P. L. Sørensen invented the pH scale by experimenting with beer” – U. Irfan, 29 May 2018 [Vox]
- “Gastrin” – H. T. Debas, 10 May 1987 [PubMed]
- “Physiologic, pathophysiologic, and pharmacologic regulation of gastric acid secretion” – M. L. Schubert, November 2017 [PubMed]
- “Esophageal pH Test for Heartburn and Acid Reflux” – J. Robinson, 23 April 2020 [WebMD]
- “Nasogastric tube errors” – Medical Protection Society, 19 September 2012 [MPS]
- “Overview – Gastroscopy” – National Health Service, 21 March 2018 [NHS]