Helicobacter Pylori Antigen (EIA) Stool Biomarker Testing
It detects active H. pylori infection from a stool sample and helps confirm cure after treatment, with convenient ordering and Quest lab access via Vitals Vault.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
This test looks for Helicobacter pylori (H. pylori) antigen in your stool. Because the antigen comes from the bacteria itself, a positive result usually means you have an active H. pylori infection in your stomach or upper small intestine.
H. pylori is a common cause of persistent indigestion (dyspepsia), gastritis, and peptic ulcers, and it can contribute to iron deficiency and low vitamin B12 in some people. The stool antigen test is also widely used as a “test of cure” after treatment.
The details matter with this test. Certain medications—especially acid-suppressing drugs—can make the result look negative even when the infection is still present, so timing and medication washout are a big part of getting an answer you can trust.
Do I need a Helicobacter Pylori Antigen EIA Stool test?
You may want this test if you have ongoing upper-abdominal discomfort, burning pain, nausea, early fullness, frequent burping, or symptoms that keep coming back despite diet changes. It is also commonly used when you have a history of ulcers, unexplained iron deficiency, or persistent indigestion that is not clearly explained by other causes.
This test is especially useful after you have completed H. pylori treatment. If you still have symptoms—or if you simply want to confirm eradication—stool antigen testing can help determine whether the bacteria is gone or whether you may need follow-up with your clinician.
You may not need stool antigen testing if you have “alarm features” such as black/tarry stools, vomiting blood, unexplained weight loss, trouble swallowing, severe anemia, or persistent vomiting. Those situations usually call for urgent medical evaluation rather than self-directed testing.
Your result is one piece of the picture. It can support clinician-directed care, but it cannot replace a full evaluation of abdominal pain, ulcer risk, medication use, and other possible causes of symptoms.
This is typically a CLIA laboratory enzyme immunoassay (EIA) for H. pylori antigen in stool; results should be interpreted with your symptoms, medication timing, and clinical history.
Lab testing
Order the H. pylori stool antigen test
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order H. pylori stool antigen testing without needing a separate doctor visit just to get the lab request. After you order, you receive clear instructions for stool collection and how to avoid common pitfalls that can affect accuracy.
When your results are ready, you can use PocketMD to review what “positive” or “negative” means in plain language, and to understand next-step questions to bring to your clinician—especially if you are testing for cure after treatment.
If your symptoms suggest you may need broader digestive evaluation, you can also add related GI-focused labs at checkout and build a more complete plan for follow-up and retesting.
- Order online and complete testing through the Quest network
- PocketMD helps you interpret results and plan next steps
- Easy retesting for post-treatment confirmation when timing is right
Key benefits of Helicobacter Pylori Antigen (EIA) Stool testing
- Detects active H. pylori infection rather than past exposure.
- Helps explain persistent dyspepsia, gastritis symptoms, and ulcer risk when the cause is unclear.
- Works well as a test-of-cure to confirm eradication after treatment when done at the right time.
- Avoids radiation and is noninvasive compared with endoscopy-based testing.
- Can guide whether you should discuss treatment, retreatment, or further evaluation with your clinician.
- Supports smarter follow-up by highlighting medication timing issues that can cause false negatives.
- Makes it easier to track your status over time with convenient reordering and PocketMD context.
What is Helicobacter Pylori Antigen (EIA) Stool?
H. pylori is a spiral-shaped bacterium that can live in the mucus layer of your stomach. In some people it triggers chronic inflammation (gastritis) and can damage the protective lining, increasing the risk of peptic ulcers in the stomach or duodenum.
A stool antigen test looks for proteins (antigens) from H. pylori that are shed into your digestive tract and passed in stool. Because the test detects bacterial antigen, it is generally used to identify an active infection and to confirm whether treatment successfully cleared the organism.
The “EIA” part refers to enzyme immunoassay, a common lab method that uses antibodies to detect the antigen. Like any test, accuracy depends on pre-test conditions—especially recent use of acid-suppressing medications or antibiotics.
Stool antigen vs. breath test
Both stool antigen testing and the urea breath test are used to detect active H. pylori. They have similar clinical roles, and the best choice often depends on availability, cost, and what is easiest for you to complete. Medication washout rules are important for both, because suppressing the bacteria can temporarily make tests look negative.
Why test-of-cure timing matters
If you test too soon after finishing antibiotics, you can get a misleading result. Most guidelines recommend waiting long enough after therapy so the test reflects true eradication rather than temporary suppression. Your clinician may also want you off certain medications before testing to reduce false negatives.
What do my Helicobacter Pylori Antigen (EIA) Stool results mean?
Low / negative H. pylori antigen
A negative result usually means H. pylori antigen was not detected, which makes an active infection less likely. If you are testing for cure, a negative result at the correct time after treatment supports eradication. However, a negative result can be falsely reassuring if you recently used proton pump inhibitors (PPIs), antibiotics, or bismuth-containing products, because these can suppress H. pylori and reduce antigen levels. If symptoms persist, it is reasonable to review medication timing and consider repeat testing or an alternative method with your clinician.
In-range (expected) result
For this test, the “expected” or “normal” outcome is typically reported as negative/not detected. When your result matches that expected range and your symptoms are improving, it often supports moving on to other causes of dyspepsia rather than treating H. pylori. If you had ulcers or significant symptoms in the past, your clinician may still consider your full history, including any prior H. pylori treatment and whether you met the recommended washout and timing for accurate testing.
High / positive H. pylori antigen
A positive result means H. pylori antigen was detected, which usually indicates an active infection. Many people with H. pylori have mild or nonspecific symptoms, but a positive test is clinically important because treatment can reduce ulcer risk and help resolve gastritis-related symptoms in many cases. Your next step is typically to discuss eradication therapy with your clinician and to plan a test-of-cure after treatment. If you have severe symptoms, bleeding, or weight loss, do not delay medical evaluation even if you already have a positive result.
Factors that influence H. pylori stool antigen results
Recent PPIs (acid blockers such as omeprazole-class medications) are a major cause of false-negative results, because they can suppress bacterial activity and antigen shedding. Recent antibiotics and bismuth-containing products can do the same, especially if taken within the weeks before testing. Watery diarrhea and improper sample handling can also affect detection in some cases, so following collection and storage instructions matters. Finally, if your pre-test probability is high (for example, classic ulcer symptoms or prior documented infection), your clinician may interpret a negative result more cautiously and consider repeat testing.
What’s included
- Helicobacter Pylori Ag, Eia, Stool
Frequently Asked Questions
Do I need to stop PPIs before an H. pylori stool antigen test?
Often, yes. PPIs can suppress H. pylori and increase the chance of a false-negative stool antigen result. The exact washout window depends on your situation and clinician guidance, so confirm what to stop and for how long before you collect the sample.
How long after antibiotics should I do a test of cure for H. pylori?
Testing too soon can be misleading because the bacteria may be temporarily suppressed. Many clinicians time stool antigen testing several weeks after finishing eradication therapy and after stopping PPIs/bismuth for an appropriate interval. If you are unsure, use PocketMD to map your medication dates and bring that timeline to your clinician.
Is stool antigen better than an H. pylori blood test?
For most people, yes. Blood antibody tests can stay positive long after the infection is gone, so they do not reliably show active infection or confirm cure. Stool antigen testing is designed to detect active infection when collected under the right conditions.
Can an H. pylori stool antigen test be wrong?
Yes. False negatives are the most common concern and are often related to recent PPIs, antibiotics, or bismuth. False positives are less common, but no test is perfect, so your symptoms, history, and timing still matter.
Do I need to fast for an H. pylori stool antigen test?
No fasting is typically required because the test uses a stool sample rather than blood. What matters more is following the collection instructions and discussing medication washout so the result reflects your true infection status.
If my test is positive, does that mean I have an ulcer?
Not necessarily. A positive result means you likely have an active H. pylori infection, which increases ulcer risk, but many people do not have an ulcer. Your clinician may decide whether you need treatment alone, additional evaluation, or (in some cases) endoscopy based on your symptoms and risk factors.
If my test is negative but I still have symptoms, what should I do next?
First, review whether PPIs, antibiotics, or bismuth could have affected the test. If timing was not ideal, repeat testing may be reasonable. If timing was appropriate, your clinician may look for other causes of dyspepsia such as reflux, medication irritation (like NSAIDs), functional dyspepsia, gallbladder issues, or other GI conditions.