The Heidelberg Test - Patient Preparation Guidelines
Pre-Appointment Preparation Guidelines
Treatment is only available after we have received your e-signed Informed Consent.
Please read these Preparation Guidelines carefully in conjunction with the Treatment Information Guide to ensure that we can maximise the efficacy of your test.

Full Contraindication
Please advise us if any of these apply as if so we cannot offer you this test for safety reasons;
- Surgery (in the last 3 months)
- Tracheotomy or Tracheostomy (in the last 3 months)
- Heart Failure
Otherwise, if you have any other concerns, please email us specifically.
Important Safety Precautions
7 days prior to the test
- Medications that affects the stomach acid, e.g. PPIs like Zantac (Ranitidin), Nexium (Esomeprasol) or Omeprasol must be stopped 7 days prior to the test. This should be done in consultation with your doctor. The same goes for antibiotics, antihistamines and other medications.
Evening before your test
- If you are taking the test in the morning, it is important that the evening meal the day before is light, without big amounts of fat or fatty acids. Do not eat any snacks before bedtime.
10-12 hours before your test
- It is very important to fast for 10-12 hours before the test.
Day of the test
- Don’t drink coffee, tea, juice, milk etc. on the morning you are taking the test. You can drink a little bit of water at room temperature, but nothing 1 hour prior to the test.
- You can eat a light breakfast. It is important that this meal is light and doesn’t contain fat or fatty acids.
- Do not eat any snacks etc.
- Do not take any kind of supplement the day of the test.
- Do not brush your teeth using toothpaste containing Sodium Bicarbonate. We suggest you brush your teeth with clean water.
- NO Alcohol or Smoking or Recreational Drugs on the day of the test.
What will happen during The Heidelberg Test?
The Heidelberg Test is a medical diagnostic test used in the diagnosis of Hypochlorhydria (reduced acid production), Hyperchlorhydria (excessive acid production), Achlorhydria (no acid production), Pyloric Insufficiency, Heavy
Stomach Mucus (from infection or ulceration), Acute and Sub-acute Gastritis.
The test will also allow the clinician to observe peristaltic activity, delayed and marked delayed emptying of the stomach (Gastroparesis) and dumping syndrome.
The testing procedure may take 1–2 hours. It is an in-clinic procedure that does not require the use of a catheter, or sedation. During testing you will sit relaxed and comfortably, without the trauma associated with other procedures.
You will need to swallow a small digital capsule about the size of a vitamin capsule. The capsule tracks acid levels in the stomach. The capsule is attached to a long thread, which is fixed on the cheek, to control the position of the capsule in the stomach. The tread still allows you to speak or drink.
After the pH measurements have been recorded, the capsule will be removed very gently or may be allowed to pass into the intestine and be expelled through the rectum.
During the test the parietal cells of the stomach will be challenged with a sodium bicarbonate solution (water and baking soda) that will cause the stomach to become neutral or alkaline. The time it takes for the stomach to reacidify back down to its original fasting acid level will determine what condition the patient has. Reacidification time is vitally important in determining hypochlorhydria, hyperchlorhydria and achlorhydria.
Important to Note
You may refuse this diagnostic test at any time, or even terminate the test whilst undergoing it by asking the clinician to stop.
The process of swallowing the capsule with a tether attached may feel unnatural and you need to make every effort to remain calm and allow the clinician to guide you through the process by not making any sudden movements or panicking.
You may perceive an initial increase in nausea-like symptoms during or immediately after the treatment due to stimulation of the gag reflex.
You may perceive a soreness of the back of the throat due to the effects of the tether as it rubs against the inside of the back of the throat.
In the unlikely event that the tethered capsule procedure fails, you authorise/request the staff to cut the tether, allowing the capsule to be consumed in order to carry out the test, despite the risk of the capsule being dumped through the pyloric sphincter, which could render the test inadequate and resulting in you having to pass the capsule through natural means or having the capsule remain in the gut without being passed.
If any unforeseen conditions arise during the course of this diagnostic test, you authorise/request the staff to perform such additional procedures and/or to render such procedures/treatments as may be deemed necessary at that time.
Please be aware that you will be asked to pay a deposit of £150 in advance of your consultation which covers the price of the capsule. This is not refundable. Should there be an issue that presents and in the unusual situation that the capsule is used but you are unable to swallow it, then the cost of the capsule will still be charged plus an administration fee for a proportion of the time spent with the clinician which is all included in your deposit.
Contact the Optimal Health Patient Service Team to book The Heidelberg Test
For non-invasive in-clinic-based testing for gastric reflux or digestive problems, visit the Optimal Health Clinic, London.
For more information or to book your consultation, you can call us, send us an email, or fill in our contact form and we’ll get back to you as soon as we can.