Interpretive Handbook

Helicobacter pylori is a spiral-shaped, gram-negative bacillus that has been associated with gastritis, gastric and duodenal ulcers, and gastric malignancies.

Helicobacter pylori is found worldwide. In Caucasian populations in the United States and other industrialized countries, Helicobacter pylori infection is infrequent in childhood. Prevalence increases 0.5% to 2% with each year of age, reaching about 50% in those who are 60 or older. Prevalence rates appear to be higher in blacks and Hispanics than in whites. In a random population of 200 apparently healthy blood donors tested for Helicobacter pylori IgG antibody, the positive rate was 27.5% with an equivocal rate of 5.5%.

The diagnosis of Helicobacter pylori gastrointestinal disease is supported by the presence of serum antibodies: IgG, IgM, or IgA, to the organism. Screening patients for the presence of antibodies to Helicobacter pylori is a convenient, noninvasive means for assessing whether gastrointestinal symptoms may be related to Helicobacter pylori infection.

Because serology may lack specificity, additional noninvasive tests can be used to confirm Helicobacter pylori infection including the urease breath test (#81590 Helicobacter pylori Breath Test) or stool antigen test for Helicobacter pylori (#81806 Helicobacter Pylori Antigen, Feces). The gold standard for diagnosis of Helicobacter pylori disease is a biopsy of infected tissue and evaluating the tissue by Gram, silver, Giemsa, or acridine orange stains; or by immunofluorescence or immunoperoxidase methods; rapid urease testing; and/or culture.

 Screening for Helicobacter pylori infection

Patients with Helicobacter pylori infection nearly always develop antibodies of the IgG class and less frequently develop antibodies of the IgA class. IgM antibodies may be produced shortly after the onset of infection. Levels of IgM antibodies should decrease after successful treatment, but may again increase if recurrence or relapse of infection occurs.

This assay should be performed only on patients with gastrointestinal symptoms because of the large percentage of Helicobacter pylori colonized individuals, especially in older age groups (estimated to be 40%-60% of asymptomatic Caucasians older than 60 years).

The serologic results must be interpreted in light of the clinical signs and symptoms of the patient.

Negative (Results with index values of <36.00 are negative.)

Equivocal (Results with index values of > or =36.00 but < or =40.00 are equivocal.)

Positive (Results with index values of >40.00 are positive.)

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