---
title: "H. pylori Testing: Stool Antigen vs Breath Test vs Blood Antibody"
type: guide
url: "https://www.test-well.com/guides/h-pylori-testing"
date_published: 2026-09-08
reviewed_at: 2026-09-08
---

# H. pylori Testing: Stool Antigen vs Breath Test vs Blood Antibody

*Which H. pylori test actually shows an active infection, what to stop taking before it, and how to confirm the bacteria are gone after treatment.*

> For a first diagnosis, order a test that detects active infection — the stool antigen test or the urea breath test; both are over 90% accurate and what gastroenterology guidelines recommend. Blood antibody tests stay positive for years after treatment, so they can't confirm a cure. Stop PPIs for 2 weeks and antibiotics for 4 weeks before testing, and retest 4+ weeks after treatment ends.

## Recommended tests

| Recommended | Type | Price | Why |
| --- | --- | --- | --- |
| [H. pylori Stool Antigen Test](https://www.test-well.com/tests/h-pylori-stool-antigen) | Test | $149.99 | Stool antigen — detects active infection; the standard first test and the test-of-cure |
| [H. pylori Breath Test](https://www.test-well.com/tests/h-pylori-breath-test-labcorp) | Test | $129.99 | Urea breath test at Labcorp — active infection, in-lab, results the same week |
| [CBC with Differential](https://www.test-well.com/tests/cbc-with-differential) | Test | $21.99 | Add if you have symptoms of bleeding (black stools, fatigue) to check for anemia |
| [Ferritin](https://www.test-well.com/tests/ferritin) | Test | $24.99 | Unexplained iron deficiency is a recognized reason to test for H. pylori |

All prices are cash-pay plus one $6 lab processing fee per order; physician authorization is included.

## Who should get tested for H. pylori?

*Helicobacter pylori* infects roughly a third of US adults and most carriers never have symptoms. Testing is worthwhile when there is a reason to treat a positive result — guidelines from the American College of Gastroenterology recommend testing (and treating if positive) for:

- Persistent upper-abdominal burning or gnawing pain, especially between meals or at night, or recurring indigestion under age 60 without red-flag symptoms
- A current or past stomach or duodenal ulcer, or a history of stomach cancer in a first-degree relative
- Unexplained iron-deficiency anemia or low ferritin once other causes are excluded
- Long-term daily aspirin or NSAID use, where H. pylori multiplies the ulcer risk
- Immune thrombocytopenia (low platelets) — eradication sometimes raises the count
- A household member who tested positive, if you have symptoms

Testing without a plan to treat is not recommended — a positive result should be followed by a 14-day antibiotic-based regimen from a clinician, then a test of cure.

## Stool antigen vs breath test vs blood antibody — what does each one measure?

**Stool antigen test.** Detects H. pylori protein in a stool sample, which only happens when live bacteria are present. Sensitivity and specificity are both about 94% with monoclonal assays. It works for diagnosis *and* for confirming eradication, and it is the easiest to collect — a small sample in the kit the lab provides, no fasting.

**Urea breath test (UBT).** You drink a solution of labeled urea; H. pylori's urease enzyme splits it and the labeled carbon appears in your breath within 15–30 minutes. Sensitivity and specificity are about 95%. It's performed at the lab, needs a 1-hour fast and no smoking beforehand, and — like the stool test — reflects active infection.

**Blood antibody (IgG) test.** Measures your immune response to the bacterium. The problem: antibodies persist for months to years after the infection is gone, so a positive result cannot distinguish a current infection from one treated a decade ago, and the test cannot be used to confirm cure. Guidelines now discourage it except where stool and breath testing aren't possible. TestWell's H. pylori offerings are stool-antigen and breath-based for this reason.

| Test | Detects active infection? | Use for test-of-cure? | Affected by PPIs / antibiotics? | Sample |
| --- | --- | --- | --- | --- |
| Stool antigen | Yes | Yes | Yes — stop first | Stool, collected at home or lab |
| Urea breath test | Yes | Yes | Yes — stop first | Breath, in-lab, 1-hour fast |
| Blood IgG antibody | Can't tell past from present | No | No | Blood |

## How should I prepare so the result is right?

Stool and breath tests look for live, active bacteria, so anything that suppresses H. pylori temporarily can produce a **false negative**:

- **Proton-pump inhibitors** (omeprazole, esomeprazole, pantoprazole, lansoprazole): stop for **2 weeks** before the sample. Famotidine (Pepcid) and antacids like Tums are fine to use in the meantime and don't affect the test.
- **Antibiotics and bismuth** (Pepto-Bismol): stop for **4 weeks** before testing.
- For the breath test: nothing to eat or drink for 1 hour before, no smoking.
- For the stool test: no special diet; collect the sample per the kit instructions and return it promptly.

If you cannot stop a PPI for two weeks — some people with severe reflux can't — tell the clinician who reviews your results; a positive test is still reliable, but a negative one is less certain.

## What does a positive result mean, and when should I retest?

A positive stool antigen or breath test means an active infection. Because H. pylori causes most ulcers and is a WHO class 1 carcinogen for stomach cancer, the standard advice is to treat every confirmed infection — usually 14 days of two antibiotics plus a PPI, sometimes with bismuth. Treatment needs a prescription, so bring the result to a clinician or use a telehealth visit.

**Test of cure.** Because first-line treatment fails 10–20% of the time (largely antibiotic resistance), guidelines recommend confirming eradication in everyone treated. Retest with a stool antigen or breath test **at least 4 weeks after finishing antibiotics** and after 2 weeks off PPIs. Never use the blood antibody test for this — it will still be positive.

A negative result with persistent symptoms points elsewhere: acid reflux, functional dyspepsia, gallbladder disease, celiac disease or medication side effects. Alarm features — trouble swallowing, vomiting, weight loss, black or bloody stools, a new problem after age 60 — warrant an endoscopy rather than another stool test.

## Frequently asked questions

### Can I test for H. pylori without seeing a doctor?

Yes. The stool antigen test and the Labcorp breath test can be ordered directly through TestWell; a licensed physician reviews the requisition and results arrive in your account. A positive result still needs a prescription for treatment, which any clinician or telehealth visit can provide from your result.

### How accurate are the H. pylori stool and breath tests?

The urea breath test and the monoclonal stool antigen test are both about 94–95% sensitive and specific and are equally accepted for diagnosis and test of cure. Blood antibody tests are less useful because they stay positive long after the infection is gone.

### Do I need to stop omeprazole before an H. pylori test?

Yes — stop proton-pump inhibitors for 2 weeks before a stool or breath test, or a true infection can read negative. Famotidine and antacids are fine to use in the meantime.

### How soon after antibiotics can I retest?

Wait at least 4 weeks after the last antibiotic dose (and 2 weeks off PPIs) before a stool antigen or breath test of cure. Testing sooner risks a false negative.

### Is H. pylori contagious?

It spreads person to person, usually in childhood within households, through saliva, vomit or stool. Adults rarely catch it anew; household members are tested if they have symptoms rather than routinely.

## Sources

- [ACG Clinical Guideline: Treatment of Helicobacter pylori Infection (2024)](https://journals.lww.com/ajg/fulltext/2024/09000/acg_clinical_guideline__treatment_of_helicobacter.14.aspx)
- [MedlinePlus (NIH) — Helicobacter Pylori (H. pylori) Tests](https://medlineplus.gov/lab-tests/helicobacter-pylori-h-pylori-tests/)
- [CDC — Helicobacter pylori: Fact Sheet for Health Care Providers](https://www.cdc.gov/ulcer/files/hpfacts.pdf)
- [Mayo Clinic — H. pylori infection: Diagnosis and treatment](https://www.mayoclinic.org/diseases-conditions/h-pylori/diagnosis-treatment/drc-20356177)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-08. Review policy: https://www.test-well.com/editorial-policy

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Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.