H. pylori Breath Test: How to Prepare

To prepare for an H. pylori breath test, stop proton pump inhibitors such as omeprazole two weeks before. Leave four weeks after any antibiotics or bismuth. Do not eat, drink or smoke for six to eight hours before, as your lab asks. These steps stop a false negative result, which would hide an infection that is there.

Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).

For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.

What is the H. pylori breath test?

H. pylori is a germ that can live in the lining of the stomach. It can cause gastritis and stomach ulcers. Many people carry it with no symptoms at all.

The germ breaks down urea, a simple substance. The test uses this. You breathe into a tube, swallow a drink or tablet with marked urea, and breathe again later. If the germ is there, the second sample holds more of the marked carbon dioxide, MedlinePlus explains.

In Spain it is called the prueba del aliento or test del aliento con urea marcada. The usual version uses urea marked with carbon-13. The Spanish family doctors' society, SEMERGEN, calls it the test of choice both to diagnose the infection and to check it has gone.

Which medicines do I need to stop before the test?

Some medicines quieten the germ without killing it. The test can then read negative while the infection is still there. That is why they must be stopped first.

• Proton pump inhibitors (PPIs): omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole. Stop them 2 weeks before. NICE sets this 2-week gap because it makes the test more accurate.
• Antibiotics for any infection: leave 4 weeks since the last dose, says NICE.
• Bismuth medicines: 4 weeks, according to SEMERGEN and the public Hospital Severo Ochoa leaflet in Madrid.
• H2 blockers such as famotidine: the Madrid leaflet asks for 2 weeks. Some UK labs only ask you to skip them on the morning of the test.
• Antacids such as sodium bicarbonate: the Madrid leaflet asks for 24 hours.

Sources do not all agree on the gaps. The MedlinePlus encyclopedia gives up to 2 weeks for antibiotics and bismuth. NICE and Spanish guidance give 4. When in doubt, use the longer gap, or ask the lab doing your test.

Is it safe to stop omeprazole before the test?

If a doctor prescribed it, ask the doctor who prescribed it before you stop. This matters most if it protects your stomach, for example after a bleeding ulcer, or alongside aspirin, anti-inflammatories or blood thinners. Sometimes the test is planned another way.

If you bought it yourself for heartburn, the burning may come back for a while during the gap.

If the burning comes back during the gap, a plain antacid can help until the day before. Read more in our guides to omeprazole in Spain and Nexium (esomeprazole).

Do I need to fast for the H. pylori breath test?

Yes. Rules vary a little between labs:

• The Frimley Health NHS leaflet asks for nothing to eat or drink for 6 hours.
• The Hospital Severo Ochoa leaflet asks for 8 hours with no food, drink or smoking.

Follow the sheet from your own lab. Bring a list of your medicines. Some test tablets contain lactose, so tell the lab if you are intolerant.

What happens on the day?

The test is simple and painless. Most people need no one to come with them.

• You breathe into a tube or bag to give a first sample.
• You take the test drink or tablet. Some labs also give a lemon-flavoured drink.
• You wait quietly. You then give a second breath sample, often about 30 minutes later.

The whole visit takes about 30 to 40 minutes. You can go back to work afterwards. MedlinePlus says breath and stool tests have no known risks.

How do I get an H. pylori breath test in Spain?

Through the public system, start with your family doctor (médico de familia) at your centro de salud. SEMERGEN notes that testing and treatment are available from primary care. The doctor gives you a request form (volante). The test is then booked at a health centre or hospital lab. SEMERGEN notes that the breath test is not available in every health area.

Privately, a doctor can request the test at a lab near you. A stool antigen test (antígeno en heces) is the main alternative. A blood antibody test is less reliable. It can stay positive after the germ has gone, so it is never used to check a cure.

Who should have the test?

Testing is not for everyone. SEMERGEN lists, among others:

• People with a stomach or duodenal ulcer, now or in the past.
• People under 55 with indigestion and no warning signs.
• Close relatives of someone with stomach cancer.
• People with iron-deficiency anaemia that has no other cause.

Children can have it too. Mayo Clinic says it suits children over 6 who can follow the steps. If you are pregnant or breastfeeding, tell your doctor before you book.

When should the test be repeated after treatment?

Treatment is a combination of medicines that needs a prescription. A check afterwards shows whether it worked. Mayo Clinic, SEMERGEN and the Public Health England guide all say to wait at least 4 weeks after finishing treatment. You also need the 2 weeks off PPIs again.

Practice differs here. In Spain, SEMERGEN advises checking that the germ has gone in everyone treated. In England, the Public Health England guide did not retest everyone routinely. The same guide calls the breath test the most accurate test. If your test is still positive, a different treatment is used.

When are stomach symptoms an emergency?

Call 112 or go to urgencias if you vomit blood or something like coffee grounds, pass black, sticky stools, have severe tummy pain, or your tummy is very painful to touch. These are warning signs listed by the NHS.

See a doctor today, without waiting, if you keep vomiting, lose weight without trying, find it hard to swallow, or feel a lump in your tummy. If you are over 55 and the indigestion is new, see a doctor soon too: SEMERGEN counts this as a warning sign. These signs may need a camera test (gastroscopia) rather than a breath test. For what stool colour can mean, see our stool colour guide.

Talking it through with a doctor by video

Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:

• Ask about your symptoms, your medicines and any warning signs.
• Explain which medicines to pause, for how long, and how to manage symptoms in the gap.
• Tell you whether a breath test, a stool test or an in-person exam fits best.

He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.

A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.

This guide is general information. It does not replace a consultation with your doctor.

Frequently asked questions

Sources

• NICE: Testing conditions for Helicobacter pylori (QS96)
• MedlinePlus: Helicobacter pylori tests
• Mayo Clinic: H. pylori infection, diagnosis and treatment
• Frimley Health NHS: Having a 13C urea breath test
• NHS: Stomach ulcer

Related guides

• H. pylori testing and treatment online
• Omeprazole in Spain
• Nexium (esomeprazole) in Spain
• Amoxicillin in Spain
• Stool colour: what it means
• Urgent Care video visit