Frequently Asked Questions

The Heidelberg pH test is a non-invasive diagnostic procedure that measures gastric acid secretion and reacidification capacity in real time. You swallow a small wireless capsule that contains a pH sensor and radio transmitter. Your practitioner administers a bicarbonate challenge at timed intervals and monitors how your stomach responds. The test takes approximately one hour and provides results during the same visit.

The capsule transmits pH data wirelessly to a receiver as it sits in your stomach. Your practitioner gives you a sodium bicarbonate solution that temporarily neutralizes your stomach acid. The capsule then measures how quickly and completely your stomach reacidifies. This challenge-reacidification cycle is repeated several times to assess both your acid production capacity and your secretory reserve.

Yes. The Heidelberg pH Capsule has been used clinically for over 60 years with no FDA recalls, no Warning Letters, and no adverse events reported in the FDA MAUDE database. The capsule is tethered for retrieval during the test and does not remain in your body. There is no sedation, no radiation, and no recovery time.

Approximately 45 to 60 minutes from swallowing the capsule to retrieval. You will be seated comfortably throughout. There is no recovery period afterward.

Fast for 8 to 12 hours before the test. Water is permitted. Avoid antacids, H2 blockers, and bismuth products for at least 48 hours. Your practitioner may ask you to discontinue PPI medication for a period before the test. Do not stop any medication without discussing it with your prescriber first. Your practitioner will provide specific instructions.

The capsule is roughly the size of a large vitamin supplement. Most patients swallow it without difficulty. The tether is a thin medical-grade thread that most patients forget is there during the test. The bicarbonate solution has a mildly salty taste.

The capsule is retrieved by your practitioner at the end of the test using the tether. This takes a few seconds. The capsule does not remain in your body.

The Heidelberg test is an out-of-pocket diagnostic procedure. Cost varies by practitioner and location. HSA and FSA funds may be eligible. Contact a provider directly for current pricing. See our cost page for more details.

The test is not currently covered by most health insurance plans. It is an out-of-pocket expense. However, as a diagnostic medical procedure, it may qualify as an eligible expense under your HSA or FSA. Confirm with your plan administrator.

The Heidelberg test is available through trained practitioners listed in our provider directory. You can search by location to find a practitioner near you. If no practitioners are available in your area, you can refer your existing doctor to us through our Refer-a-Doctor form.

The Heidelberg test measures gastric acidity and aids in the diagnosis of hypochlorhydria, achlorhydria, and hyperchlorhydria. That is its intended use. Many conditions including SIBO, reflux, and nutrient malabsorption are associated with abnormal gastric acid levels. The test provides objective data that your practitioner interprets in the context of your full clinical picture. It does not diagnose conditions beyond its intended use.

The Heidelberg pH Capsule is a Class I medical device that is 510(k)-exempt. It has been legally marketed in the United States since before the Medical Device Amendments of 1976. Heidelberg Medical, Inc. is a registered medical device establishment with the FDA, and the device is listed with the FDA. Registration and listing do not denote FDA approval, clearance, or endorsement (21 CFR §807.39).

Your practitioner may ask you to discontinue your PPI for a period before the test so that your natural acid production can be assessed. The duration of the hold depends on the specific medication and your clinical situation. Do not stop any medication without first discussing it with your prescriber. Your practitioner will provide specific guidance.

Your practitioner will review your results with you during the same visit and explain what the patterns mean in the context of your symptoms and history. If you have additional questions after the visit, contact your practitioner directly. The test provides data. Your practitioner provides the clinical interpretation and recommendations.

The Heidelberg pH Capsule has been used continuously for over 60 years and is supported by more than 140 peer-reviewed publications. It is well established in functional and integrative medicine, pharmaceutical research, and academic gastroenterology. It has not been widely marketed to the general public, which is why many patients and primary care physicians are unfamiliar with it. That does not reflect on the test’s validity or clinical track record.