Helicobacter pylori – Serology

Testing Indications

Serological testing for evidence of H. pylori infection can be used as part of the initial investigation of patients suspected of having one of the following conditions: 

• active peptic ulcer disease 
• a past history of documented peptic ulcer disease 
• atrophic gastritis/chronic gastritis 
• gastric adenocarcinoma 
• gastric MALT lymphoma 
• un-investigated dyspepsia (age < 45-55 years, and no alarm symptoms) 
• prior to long-term non-steroidal anti-inflammatory drugs use

Limitations

• Hemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.
• Serologic testing of asymptomatic individuals is rarely indicated because of the low predictive value of the test in this population (exceptions include family members of patients diagnosed with gastric cancer). 
• The H.pylori IgG antibody test cannot reliably determine eradication.  Serological follow up testing of individuals with positive H. pylori serology is not advised. 
• Specimens are stable for 8 days 2-8°C or 6 months at -20°C. 
• Results from specimens received after 8 days from collection date may be unreliable.
• The LIAISON® H. pylori IgG assay has not been evaluated in a pediatric population.

Storage and Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Special Instructions

To prevent erroneous results due to the presence of fibrin, ensure that complete clot formation has taken place prior to centrifugation of samples. Centrifuge if using SST. Place specimen in biohazard bag and ship to PHOL on ice packs.

Test Frequency and Turnaround Time (TAT)

Helicobacter pylori - serology testing is performed daily Monday to Friday. 

Turnaround time is up to 7 days from receipt by PHO Laboratory

Helicobacter pylori (H. pylori) - serology testing is performed on the DiaSorin LIAISON^®. The LIAISON^® H. pylori IgG assay is a two-step, indirect chemiluminescence immunoassay (CLIA) for qualitative determination of IgG antibodies to H. pylori.

Interpretation

1. A negative result generally indicates that the patient has not been infected, but does not always rule out acute H. pylori infection. No further testing is required.
2. A positive result indicates the presence of detectable IgG antibody to H.  pylori. No further testing is required.
3. Indeterminate result: A new specimen should be collected and submitted for testing. If there is ongoing clinical suspicion of H. pylori infection, suggest single repeat serology after 2-4 weeks if not already repeated.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Test results are reported as positive, negative or equivocal for the presence of IgG antibodies to H. pylori. However, diagnosis of infectious diseases should not be established on the basis of a single test result, but should be determined in conjunction with clinical findings and other diagnostic procedures.