Helicobacter pylori is a bacterium commonly found in the mucous layer of the human stomach. It is unique because it can survive the stomach’s highly acidic environment, allowing it to colonize the gastric lining for years. Testing is typically initiated when a person experiences persistent symptoms such as chronic indigestion, abdominal discomfort, or signs of a stomach ulcer. Understanding the results of an H. pylori test is important for managing digestive health.
What Does an IgG Positive Result Indicate
A positive result on the H. pylori Immunoglobulin G (IgG) test means the body has produced specific antibodies in response to exposure to the bacterium. IgG antibodies are proteins generated by the immune system to combat pathogens. Their presence confirms that the individual has encountered H. pylori and mounted an immunological defense.
The IgG test detects this historical immune response, but it has a significant limitation: it cannot reliably distinguish between a current, active infection and a past infection that has already been successfully cleared. IgG antibodies tend to remain in the blood for an extended period, often months or years after the bacteria have been eliminated. Therefore, a positive IgG result only indicates past exposure.
Because of this persistence, the IgG test is not the preferred method for diagnosing an ongoing infection. To determine if the bacteria are currently present and active in the stomach, a healthcare provider typically orders other tests. These methods look for the actual presence of the organism or its metabolic products. A Urea Breath Test (UBT) or a Stool Antigen Test is often used to establish a definitive diagnosis of an active H. pylori infection.
Associated Health Risks
When an H. pylori infection is active and remains untreated, the chronic presence of the bacteria can lead to specific health problems due to persistent inflammation. Colonization of the stomach lining causes a continuous inflammatory response known as chronic gastritis. This sustained inflammation can damage the protective mucosal layer, making the stomach and duodenum susceptible to acid damage.
The most recognized complication is Peptic Ulcer Disease (PUD), where sores develop in the lining of the stomach (gastric ulcers) or the upper small intestine (duodenal ulcers). Although only 10 to 20 percent of infected people develop an ulcer, H. pylori is responsible for the majority of these cases. Chronic irritation can also progress to atrophic gastritis, involving the loss of acid-producing glands.
H. pylori infection is also associated with an increased risk of developing certain gastric malignancies. The bacterium is classified as a Group 1 carcinogen, meaning it is a definite cause of cancer in humans. Chronic infection increases the risk for gastric adenocarcinoma, the most common form of stomach cancer. It is also strongly linked to mucosa-associated lymphoid tissue (MALT) lymphoma, which often regresses after successful eradication.
When is Treatment Necessary and What Does it Involve
Treatment for H. pylori is typically not initiated based on a positive IgG test alone, as that result only signifies exposure. Therapy is reserved for patients who have symptoms and a confirmed active infection, usually via a Urea Breath Test or Stool Antigen Test. The goal of treatment is to completely eliminate the bacteria from the stomach, a process known as eradication.
The standard treatment regimen involves a multi-drug approach, often called triple or quadruple therapy, to counteract the bacteria’s ability to resist single antibiotics. These regimens last for 10 to 14 days and combine a Proton Pump Inhibitor (PPI) with two or more antibiotics. The PPI reduces stomach acid production, which helps the antibiotics work more effectively and allows the inflamed lining to heal.
Common antibiotic combinations include amoxicillin, clarithromycin, and metronidazole; specific drugs depend on regional resistance patterns. Bismuth-based quadruple therapy, which adds bismuth subsalicylate to the regimen, is often preferred as a first-line option due to rising antibiotic resistance rates. Adherence to the full course of medication is important, as stopping treatment early can lead to failure and contribute to antibiotic-resistant strains.
Confirming Eradication
After completing the full course of antibiotic therapy, confirming successful eradication is an important next step. The serology test that initially showed the positive IgG result is not suitable for this purpose. Since IgG antibodies can persist in the bloodstream for a long time, the test may remain positive even after the bacteria are completely gone, leading to a misleading result.
To confirm successful eradication, follow-up testing must detect the active presence of the organism. The Urea Breath Test and the Stool Antigen Test are the preferred non-invasive tests for this confirmation. To ensure accuracy, secondary testing is typically delayed until at least four weeks after antibiotic therapy is finished.
Patients are generally recommended to temporarily stop taking their Proton Pump Inhibitor (PPI) medication for one to two weeks before the follow-up test. PPIs can temporarily suppress the bacteria’s activity, potentially causing a false-negative result on the UBT or Stool Antigen Test. A negative result on these confirmation tests indicates that the treatment successfully cleared the infection.