Specimen Required

Serology: Suitable specimens are individual samples (human sera or EDTA/heparinized/citrated plasma) obtained by standard laboratory techniques.

Specimen Minimum Volume

0.6ml

Transport Temperature

*Storage at 2-8^°C should not exceed 14 days.

**For longer delay, freeze at -70^°C and transport on dry ice.

Reject Due To

Useful For

As a primary screening method for diagnosis of untreated Helicobacter pylori infection persons < 55 years old.

Clinical Information

Helicobacter pylori is the main cause of peptic ulcer disease and a major risk factor for gastric cancer. Individuals infected with H. pylori may develop acute gastroenteritis (abdominal pain, nausea, and vomiting) within 2 weeks following infection. H. pylori establish a chronic infection in the majority of individuals, represented by chronic gastritis of different types.

Approximately 50% of the world’s population is infected with H. pylori. In developed countries a progressive increase in the prevalence is observed, from a low percentage of infection in children to 40 – 50% infection rates in the older age groups. This is not the consequence of a progressive acquisition of the infection but rather the result of a cohort effect. The majority of subjects acquire the infection in childhood, and the infection persists lifelong. Thus, if the oldest individuals have a higher H. pylori infection prevalence, it is because the risk of becoming infected was higher when they were children.

Serological testing represents a primary screening method for the diagnosis of H. pylori infection. In contrast to serum IgM levels, serum IgG and IgA levels persist for months to years and correlate with active infection in untreated individuals. Only a small percentage of individuals do not have detectable systemic seroconversion following infection. Anti-H. pylori serum IgG levls are more consistently elevated than serum IgA levels. Therefore, serum IgG immunoassays yield greater sensitivity and specificity than serum IgA assays.

In contrast to diagnosis, serum antibody levels are not recommended for patient follow up. Urea breath test or stool antigen detection is more suitable for determining treatment success and reinfection.

Reference Values

NONREACTIVE

Interpretation

A REACTIVE test result is evidence for the presence of antibodies specific to H. pylori, but does not allow differentiating between an active infection and (asymptomatic) colonization by H. pylori and does not prove conclusively the existence of a gastro-intestinal illness. Antigenic cross-reactivity with Campylobacter cannot be excluded.

A NONREACTIVE IgG result does not exclude infection as 2 – 7% of patients may have no detectable IgG in spite of obvious infection.

Clinical Reference

Blaser, M. J. 2010. Helicobacter pylori and Other Gastric Helicobacter Species, p. 2803-2813. In Mandell, D., Bennett, J. E., and Dolin, R. Principles and practice of infectious diseases, 7^th ed., vol. 2. Churchill Livingstone, Elsevier, Philadelphia, PA.

Fox, J. G., and Megraud, F. 2007. Helicobacter, p. 947-962. In Murray, P. R., Baron, E. J., Jorgensen, J. H., Landry, M. L., and Pfaller, M. A. Manual of Clinical Microbiology, 9^th ed., vol. 2. ASM Press, American Society for Microbiology, Washington, DC.

Method Description

Enzyme-linked immunosorbent assay (ELISA)

Performing Laboratory Location

Newfoundland & Labrador Public Health Laboratory

St. John’s