Helicobacter Test INFAI for Children: Uses, Dosage & Side Effects

What Is Helicobacter Test INFAI and What Is It Used For?

Helicobacter pylori is a gram-negative, microaerophilic bacterium that colonizes the gastric mucosa of the human stomach. It is one of the most common chronic bacterial infections worldwide, affecting an estimated 4.4 billion people globally according to World Health Organization (WHO) estimates. The prevalence varies significantly by geographic region, socioeconomic status, and age, with rates ranging from approximately 20–30% in high-income countries to 70–90% in low-income regions. In children, infection is typically acquired during early childhood, most commonly through intrafamilial transmission.

H. pylori infection in children is clinically significant because it is the primary cause of chronic gastritis and peptic ulcer disease in the pediatric population. While the majority of infected children remain asymptomatic, a proportion develop symptoms including recurrent abdominal pain, nausea, vomiting, and poor appetite. Furthermore, untreated H. pylori infection that persists into adulthood is associated with increased risk of gastric ulcers, duodenal ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. The International Agency for Research on Cancer (IARC) has classified H. pylori as a Group 1 carcinogen – a definite cause of cancer in humans.

The Helicobacter Test INFAI for children aged 3–11 years is an in vivo diagnostic test that exploits a unique biochemical characteristic of H. pylori: the bacterium produces large amounts of the enzyme urease. Urease is critical for H. pylori's survival in the hostile acidic environment of the stomach because it hydrolyzes urea into ammonia and carbon dioxide. The ammonia neutralizes gastric acid in the immediate microenvironment surrounding the bacterium, creating a protective alkaline buffer that allows H. pylori to colonize and persist in the gastric mucosa. No other common gastric pathogen produces urease at comparable levels, which makes this enzymatic activity an excellent diagnostic target.

The test contains 45 mg of 13C-urea, a form of urea in which the carbon atom is the stable isotope carbon-13 (13C) rather than the more abundant carbon-12 (12C). Importantly, 13C is a naturally occurring stable isotope – it is not radioactive and poses no radiation risk. This distinguishes the Helicobacter Test INFAI from the older 14C-urea breath test, which uses the radioactive isotope carbon-14 and is therefore unsuitable for children and pregnant women. The 13C-urea powder is dissolved in approximately 200 mL of 100% orange juice (preferred) or apple juice. The acidic citrus juice serves a dual purpose: it delays gastric emptying (keeping the test solution in contact with the gastric mucosa for longer) and provides a palatable drink for the child.

When the child drinks the solution, the 13C-urea comes into direct contact with the gastric mucosa. If H. pylori is present, the bacterium's urease enzyme rapidly hydrolyzes the 13C-urea into 13C-labeled carbon dioxide (13CO2) and ammonia (NH3). The 13CO2 is absorbed through the gastric and intestinal mucosa into the bloodstream, transported to the lungs, and exhaled in the breath. By collecting breath samples before and 30 minutes after the test solution is consumed, and comparing the ratio of 13C to 12C in the exhaled CO2 using isotope ratio mass spectrometry (IRMS) or non-dispersive infrared spectroscopy (NDIRS), the laboratory can determine whether the 13C/12C ratio has increased above a defined threshold. An increase above the cut-off value (typically a delta over baseline of 3.5–4.0 per mille for children) indicates that urease activity is present in the stomach, which is diagnostic of active H. pylori infection.

The 13C-urea breath test has been extensively validated in pediatric populations. A systematic review and meta-analysis published in the Journal of Pediatric Gastroenterology and Nutrition reported a pooled sensitivity of 95.9% (95% CI: 91.8–98.0%) and pooled specificity of 97.7% (95% CI: 95.4–98.9%) in children. These performance characteristics are comparable to invasive diagnostic methods such as endoscopic biopsy with histological examination, rapid urease test (CLOtest), and culture, making the breath test the preferred non-invasive alternative when endoscopy is not clinically indicated. The test is also considered superior to the stool antigen test (which has a slightly lower sensitivity of approximately 90–95% in children) and significantly more reliable than serology (antibody blood tests), which cannot distinguish between active and past infection.

According to the joint ESPGHAN/NASPGHAN guidelines for the management of Helicobacter pylori in children and adolescents (2017), the 13C-urea breath test is the recommended non-invasive test for:

• Confirmation of H. pylori eradication: The primary recommended use. The test should be performed at least 4 weeks after completing antibiotic eradication therapy and at least 2 weeks after stopping PPIs to confirm that the infection has been successfully eliminated.
• Initial non-invasive diagnosis: When a “test-and-treat” strategy is not recommended in children, the breath test can still be used as part of the diagnostic workup, particularly in settings where endoscopy is not readily available or when the clinical situation does not warrant an invasive procedure.
• Epidemiological studies: The non-invasive nature and high accuracy of the breath test make it ideal for population-based prevalence studies in children.

What Should You Know Before Using Helicobacter Test INFAI?

Contraindications

The Helicobacter Test INFAI for children should not be used if the child has a known hypersensitivity (allergy) to 13C-urea or to any of the other ingredients in the formulation. Although allergic reactions to 13C-urea are exceedingly rare given that urea is a naturally occurring substance in the human body, parents and healthcare providers should report any suspected adverse reactions.

The test is not intended for use in children under 3 years of age. This age restriction exists because reliable breath sample collection from very young children is technically challenging, and the diagnostic performance of the test has not been adequately validated in this age group. For children under 3 with suspected H. pylori infection, alternative diagnostic approaches should be discussed with a pediatric gastroenterologist.

The test should not be used in children with known or suspected gastric infection by organisms other than H. pylori that may also produce urease (such as Helicobacter heilmannii), as this could lead to false positive results, although such infections are extremely uncommon in the pediatric population. The test should also not be performed if the child has recently undergone gastric surgery, as altered anatomy may affect the test's reliability.

Warnings and Precautions

Several important factors must be considered before performing the Helicobacter Test INFAI to ensure accurate results:

• Proton pump inhibitors (PPIs): Medications such as omeprazole, esomeprazole, lansoprazole, and pantoprazole must be discontinued at least 2 weeks (14 days) before the test. PPIs increase gastric pH, which can suppress H. pylori urease activity and reduce the bacterial load in the stomach without eradicating the infection, leading to false negative results. The attending physician should be consulted about appropriate alternative medications for acid suppression during the washout period if needed.
• Antibiotics: Any antibiotic therapy must be completed at least 4 weeks (28 days) before the test. Antibiotics, even those not specifically targeted at H. pylori, can suppress the bacterium and reduce its urease activity. This includes commonly prescribed pediatric antibiotics such as amoxicillin, clarithromycin, metronidazole, and azithromycin.
• Bismuth preparations: Bismuth subsalicylate (e.g., Pepto-Bismol) and bismuth subcitrate must be stopped at least 4 weeks before testing. Bismuth compounds have direct antimicrobial activity against H. pylori and can suppress the bacterium enough to cause false negative results.
• H2 receptor antagonists: While the effect of H2 blockers (such as ranitidine, famotidine) on the breath test is less pronounced than PPIs, some guidelines recommend stopping these medications at least 24–48 hours before testing as a precaution.
• Fasting requirement: The child must fast for a minimum of 6 hours before the test. The test is ideally performed in the early morning after an overnight fast. Only water is permitted during the fasting period. Food in the stomach can interfere with the absorption and metabolism of the test solution and produce variable results.

Special Populations

The Helicobacter Test INFAI for children is specifically formulated and validated for children aged 3 to 11 years. For adolescents aged 12 years and older, the adult formulation of the Helicobacter Test INFAI (containing 75 mg of 13C-urea) should be used instead. For children under 3 years, the test should not be used, and the diagnosis of H. pylori infection should be based on alternative methods as determined by a pediatric gastroenterologist, typically involving endoscopy with biopsy if clinically warranted.

Children with significant gastric motility disorders, short bowel syndrome, or other conditions that substantially alter gastrointestinal physiology may produce unreliable test results. In such cases, the treating physician should consider alternative diagnostic approaches or interpret the breath test results in conjunction with other clinical findings.

Factors Affecting Test Accuracy

In addition to the medication-related factors described above, several other conditions can influence the accuracy of the 13C-urea breath test. Active upper gastrointestinal bleeding can cause false negative results because blood in the stomach may interfere with the test substrate. Achlorhydria (absence of gastric acid) from any cause may also affect results, as the acidic environment is important for optimal urease activity. Following partial gastrectomy or other gastric surgery, the altered anatomy and physiology may affect test reliability, and results should be interpreted with caution. Finally, recent vomiting or significant dehydration in the child may affect the accuracy of breath sample collection and should be addressed before proceeding with the test.

How Does Helicobacter Test INFAI Interact with Other Drugs?

The Helicobacter Test INFAI is a single-use diagnostic agent, not a therapeutic medication taken regularly. The 13C-urea is a simple molecular compound that is not metabolized by hepatic cytochrome P450 enzymes and does not bind to plasma proteins. It does not accumulate in the body and has no pharmacological activity beyond serving as a substrate for H. pylori urease. Therefore, in the traditional pharmacological sense, 13C-urea does not have drug-drug interactions.

However, the clinical interpretation of the breath test can be significantly affected by medications that alter the gastric environment or suppress H. pylori activity. These drug-test interactions are critically important to understand, as they can lead to false negative results – meaning the test shows no infection when the child is actually infected with H. pylori.

It is important to note that the interactions listed above are drug-test interactions (affecting diagnostic accuracy) rather than drug-drug interactions (affecting the pharmacokinetics or pharmacodynamics of either substance). The 13C-urea itself is metabolically inert in the absence of bacterial urease and is harmlessly absorbed, metabolized via normal urea cycle pathways, and excreted by the kidneys as part of the body's routine nitrogen metabolism.

Parents should inform the testing physician or nurse about all medications, supplements, and over-the-counter products the child is taking, even those that are not listed above. This comprehensive medication review ensures that the healthcare provider can make an informed decision about the optimal timing for the breath test and the reliability of the results. If the child has been on a medication that requires a washout period, the test should be rescheduled accordingly.

There is no known interaction between the 13C-urea breath test solution and the orange or apple juice used to dissolve it. The juice serves as a test meal that delays gastric emptying and does not affect the diagnostic properties of the 13C-urea. However, carbonated drinks should be avoided as the vehicle, as the CO2 they contain may theoretically interfere with baseline 13CO2 measurements.

What Is the Correct Dosage and Procedure for Helicobacter Test INFAI?

Children Aged 3–11 Years

The complete test procedure is performed under medical supervision in a clinical setting (hospital outpatient clinic, pediatric gastroenterology unit, or GP surgery). It follows a standardized protocol to ensure accurate and reproducible results:

1. Preparation (pre-test): Confirm that the child has fasted for at least 6 hours. Verify that all medication washout periods have been observed (PPIs ≥ 2 weeks, antibiotics/bismuth ≥ 4 weeks). Record any medications the child is currently taking. Label the two breath collection bags (T0 for baseline and T30 for post-dose).
2. Baseline breath sample (T0): Have the child exhale normally through a straw into the first collection bag labeled T0. The child should breathe in through the nose and exhale slowly through the straw. Once the bag is adequately inflated, seal it immediately. This sample represents the child's baseline 13C/12C ratio in exhaled CO2.
3. Test solution preparation: Open the sachet containing 45 mg of 13C-urea powder. Pour the powder into a cup containing approximately 200 mL of 100% orange juice (recommended) or 100% apple juice. Stir gently until the powder is completely dissolved. The solution should be clear and colorless in the juice.
4. Drinking the solution: Have the child drink the entire test solution. There is no specific time limit for drinking, but the child should consume the full volume. Note the time of ingestion.
5. Waiting period (30 minutes): The child should remain seated and resting for exactly 30 minutes. During this time, the child should not eat, drink, or engage in vigorous physical activity. Quiet activities such as reading, drawing, or watching a tablet are permitted and encouraged.
6. Post-dose breath sample (T30): Exactly 30 minutes after ingesting the test solution, have the child exhale through a straw into the second collection bag labeled T30. Seal the bag immediately. Both samples are then sent to the laboratory for analysis.

Adolescents (12 Years and Older) and Adults

Children aged 12 years and older should use the adult formulation of Helicobacter Test INFAI, which contains 75 mg of 13C-urea rather than the 45 mg pediatric dose. The test procedure is otherwise identical. The adult formulation also uses 200 mL of orange or apple juice as the vehicle and follows the same 30-minute protocol with baseline (T0) and post-dose (T30) breath samples.

Interpreting Results

The laboratory analyzes both breath samples using isotope ratio mass spectrometry (IRMS) or non-dispersive infrared spectroscopy (NDIRS). The result is expressed as a “delta over baseline” (DOB) value in per mille (‰), which represents the change in the 13C/12C ratio between the T30 and T0 samples.

It is important to note that the specific cut-off value may vary slightly between laboratories depending on the analytical method used and the laboratory's own validated reference ranges. The treating physician will interpret the results in the context of the child's clinical presentation and medical history. A positive result indicates the need for consideration of eradication therapy, while a negative result after treatment confirms successful eradication.

Repeat Testing

The Helicobacter Test INFAI can be safely repeated as many times as clinically necessary. Because 13C is a stable, non-radioactive isotope, there is no cumulative radiation risk, and the test can be used for serial monitoring. When used to confirm eradication after treatment, the test should be performed no earlier than 4 weeks after completing antibiotic therapy and 2 weeks after stopping PPIs. If the initial result is borderline (DOB between 3.5 and 4.0‰), the test can be repeated after 4 weeks, or an alternative diagnostic method (such as the stool antigen test or endoscopy) can be considered.

What Are the Side Effects of Helicobacter Test INFAI?

The Helicobacter Test INFAI for children is one of the safest diagnostic products in clinical use. The active substance, 13C-urea, is chemically identical to the urea naturally produced by the human body as part of nitrogen metabolism, differing only in the isotopic composition of its carbon atom (13C instead of 12C). Both isotopes are naturally occurring, stable, and non-radioactive. The 45 mg dose of 13C-urea used in the test is trivially small compared to the approximately 30–50 grams of urea that the body naturally produces and excretes daily.

In the extensive clinical development program and subsequent post-marketing surveillance of the Helicobacter Test INFAI, no adverse drug reactions have been identified that can be attributed to the 13C-urea test substance itself. The European Medicines Agency (EMA) Summary of Product Characteristics (SmPC) does not list any known side effects for this product.

The side effect frequency grid below reflects the current state of pharmacovigilance data:

It is worth emphasizing that the Helicobacter Test INFAI carries no radiation risk. Unlike the 14C-urea breath test (which uses the radioactive isotope carbon-14 and delivers a small radiation dose equivalent to approximately 1 day of natural background radiation), the 13C-urea breath test uses a stable isotope with zero radiation exposure. This is one of the primary reasons why the 13C formulation is specifically preferred for use in children and is the only breath test formulation approved for pediatric use in most countries.

If a child experiences any unexpected symptoms during or after the test, parents should inform the healthcare provider. Although adverse reactions to 13C-urea are not expected based on the substance's pharmacological properties, all medical products are subject to ongoing safety monitoring, and reporting any suspected adverse reactions contributes to the safety database.

The citrus juice used as the vehicle for the test solution may, in very rare cases, cause mild gastrointestinal discomfort in children with known citrus sensitivity or reflux. If a child cannot tolerate orange juice, 100% apple juice is an acceptable alternative. Parents should inform the healthcare provider if the child has any known food allergies or intolerances before the test.

How Should You Store Helicobacter Test INFAI?

The Helicobacter Test INFAI for children should be stored in accordance with standard pharmaceutical storage guidelines to ensure the integrity and accuracy of the diagnostic product. Proper storage is important because degradation of the 13C-urea could potentially affect the reliability of the test results, although 13C-urea is a chemically stable compound under normal storage conditions.

The following storage conditions should be observed:

• Temperature: Store below 25°C (77°F). The product does not require refrigeration. Store at room temperature, avoiding exposure to excessive heat. Do not freeze the product.
• Light and moisture: Keep the sachets in the original packaging until use. The foil sachets protect the powder from moisture absorption, which is important because urea is hygroscopic (it absorbs moisture from the air). Do not remove the powder from the sachet until immediately before use.
• Expiry date: Do not use the product after the expiry date (EXP) printed on the sachet and on the outer carton. The expiry date refers to the last day of that month. Expired test kits should be disposed of according to local pharmaceutical waste disposal guidelines; do not flush down the toilet or discard in household waste unless local regulations permit this.
• Prepared solution: Once the 13C-urea powder has been dissolved in juice, the test solution must be used immediately. Do not store the prepared solution for later use, as the stability of 13C-urea in acidic juice has not been validated beyond the time required for the test procedure.
• Breath collection bags: The sealed breath collection bags (T0 and T30) should be sent to the laboratory as soon as possible, ideally within 24 hours of collection. The bags should be stored at room temperature and protected from direct sunlight until dispatch. Most modern collection systems maintain stable CO2 isotope ratios for several days when properly sealed.
• Keep out of reach of children: As with all medicines and diagnostic products, the Helicobacter Test INFAI should be stored out of the sight and reach of children. While accidental ingestion of the 13C-urea powder is not expected to cause harm (it is the same substance used in the test and is metabolized normally), unsupervised access to medical products should always be prevented.

Healthcare facilities performing the breath test should maintain appropriate inventory management to ensure that test kits are used before their expiry date and that storage conditions are monitored. The test kits should be stored in a clean, dry area away from direct heat sources and not in locations where temperature fluctuations are common, such as near windows or heating vents.

What Does Helicobacter Test INFAI Contain?

The Helicobacter Test INFAI for children aged 3–11 years has a remarkably simple formulation. Unlike most pharmaceutical products, which contain multiple excipients (inactive ingredients) alongside the active substance, the test powder consists solely of the active ingredient:

• Active substance: 13C-urea (carbon-13 labeled urea) – 45 mg per sachet. This is a white, crystalline powder with the molecular formula CO(NH2)2, where the carbon atom is the stable isotope 13C rather than the more common 12C. The enrichment level of 13C is at least 99 atom percent, meaning virtually all the carbon in the urea is the heavier isotope.
• Excipients: None. The sachet contains only 13C-urea powder with no additional fillers, binders, flavoring agents, or preservatives.

The complete Helicobacter Test INFAI kit for children typically includes the following components:

The 13C-urea used in the test is produced by chemical synthesis using 13C-enriched precursors. The isotopic enrichment must meet strict quality standards to ensure that the difference between the 13C/12C ratio in the baseline and post-dose breath samples is reliably detectable. The manufacturing process is subject to Good Manufacturing Practice (GMP) regulations and the product undergoes rigorous quality control testing for isotopic purity, chemical identity, and microbial contamination before release.

The orange or apple juice used to dissolve the powder is not included in the kit and must be provided by the testing facility. It is important to use 100% fruit juice (not juice drinks, cordials, or carbonated beverages) to ensure consistent test meal characteristics. The juice serves as a “test meal” that delays gastric emptying, prolonging contact between the 13C-urea and the gastric mucosa. Orange juice is preferred because its citric acid content is particularly effective at delaying gastric emptying.

The product contains no lactose, gluten, gelatin, soy, peanut, tree nut, or other common allergens. There are no animal-derived ingredients. The product is suitable for children with food allergies (provided they can tolerate the juice used as the vehicle) and for families following vegetarian or vegan diets.