Helicobacter pylori – Antibody (IgG)

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Background
This page provides IgG antibody (serology) testing information for Helicobacter pylori at Public Health Ontario (PHO).

Alternative noninvasive H. pylori testing methods such as urea breath test, stool antigen, or stool PCR are not available at PHO, but may be available at other private or hospital laboratories. Invasive biopsy testing methods such as histology, rapid urease, or direct culture are also not available at PHO.

Updates
As of July 31, 2024, clarifications regarding testing indications and availability at PHO have been added.

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 21 nov. 2024.

Testing Indications

The main established testing and treatment indications for H. pylori in adults and children are documented peptic ulcers or gastric cancers (including MALT lymphoma). In adults, other conditional indications may include unexplained dyspepsia, chronic nonsteroidal anti-inflammatory drug (NSAID) or chronic aspirin use, or unexplained refractory iron deficiency anemia despite appropriate evaluation. There is insufficient evidence to support routine testing and treating of H. pylori in asymptomatic individuals.¹

As per Choosing Wisely, serology is no longer a recommended primary testing method for diagnosis of active H. pylori infection. Instead, alternative non-invasive methods such as stool antigen or urea breath tests should be preferentially used in adults with no alarming signs. Although these alternative methods are not available at PHO, such tests may be offered at other community laboratories (e.g. private or hospital laboratories). Individuals with alarming signs, as well as some pediatric populations, may warrant endoscopic evaluation as opposed to non-invasive testing.^2,3

Acceptance/Rejection Criteria

H. pylori serology samples must be received at PHO’s laboratory within 8 days of collection to be tested, otherwise the samples will be rejected with a cancellation comment.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
H. pylori IgG and/or antibody and/or serology	General Test Requisition	Serum	5 mL of clotted whole blood or 0.5 mL serum	Blood, clotted – serum separator tube (SST)

Submission and Collection Notes

Complete all fields of the General Test Requisition form.

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

Limitations

Grossly haemolysed, lipemic, contaminated specimens and specimens containing anticoagulant are unsuitable for testing.

Storage and Transport

Centrifuge if using SST. To prevent erroneous results due to the presence of fibrin, ensure that complete clot formation has taken place prior to centrifugation of samples.
Specimens should be stored at 2-8°C following collection and shipped on ice packs to PHO’s laboratory within 8 days of collection date. All clinical specimens must be shipped in accordance with the Transportation of Dangerous Goods Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

H. pylori IgG serology is performed Monday to Friday at PHO’s laboratory. Turnaround time is up to 7 days from receipt at PHO’s laboratory.

Test Methods

Method: Helicobacter pylori serology is performed using the Diasorin LIAISON H. pylori IgG assay. The assay is an indirect chemiluminescence immunoassay (CLIA) that provides qualitative detection of IgG antibodies to H. pylori antigens in serum.

Performance: Approximate sensitivity of H. pylori serology has traditionally been estimated between 85% and 95%, and specificity has been estimated between 70% and 90%.^4,5,6

Limitations: Due to the lower test specificity, false positives may occur in low prevalence settings. Seropositivity alone does not distinguish active from resolved infection. Clinical assessment and additional testing with a stool antigen or urea breath test may be considered if clinically indicated. Serological follow-up testing of individuals after primary diagnosis is not advised, since serology may remain positive despite successful eradication. The assay has not been evaluated in pediatric populations and results should be interpreted with caution.

Interpretation

The following table provides possible test results with associated interpretations:

H. pylori IgG CLIA Result	Interpretation
Negative	A negative result generally indicates that the patient has not been infected, but does not always rule out acute H. pylori infection.
Positive	A positive result indicates the presence of detectable IgG antibody to H. pylori. False positives may occur, therefore clinical correlation is required. A positive result does not distinguish active from resolved infection.
Equivocal	Results are inconclusive. Repeat testing may be indicated if there is ongoing clinical suspicion of H. pylori infection.

Reporting

Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

References

Chey WD, Leontiadis GI, Howden CW, Moss SF. ACG Clinical Guideline: Treatment of Helicobacter pylori Infection. Am J Gastroenterol. 2017 Feb;112(2):212-239. doi: 10.1038/ajg.2016.563.
American Academy of Family Physicians. Don’t request serology for Helicobacter pylori. American Family Physician Choosing Wisely Collection, 318. Available online at: https://www.aafp.org/pubs/afp/collections/choosing-wisely/318.html
Jones NL, Koletzko S, Goodman K, Bontems P, Cadranel S, Casswall T, Czinn S, Gold BD, Guarner J, Elitsur Y, Homan M, Kalach N, Kori M, Madrazo A, Megraud F, Papadopoulou A, Rowland M; ESPGHAN, NASPGHAN. Joint ESPGHAN/NASPGHAN Guidelines for the Management of Helicobacter pylori in Children and Adolescents (Update 2016). J Pediatr Gastroenterol Nutr. 2017 Jun;64(6):991-1003. doi: 10.1097/MPG.0000000000001594.
Xie F, O'Reilly D, Ferrusi IL, Blackhouse G, Bowen JM, Tarride JE, Goeree R. Illustrating economic evaluation of diagnostic technologies: comparing Helicobacter pylori screening strategies in prevention of gastric cancer in Canada. J Am Coll Radiol. 2009 May;6(5):317-23. doi: 10.1016/j.jacr.2009.01.022.
Elwyn G, Taubert M, Davies S, Brown G, Allison M, Phillips C. Which test is best for Helicobacter pylori? A cost-effectiveness model using decision analysis. Br J Gen Pract. 2007 May;57(538):401-3.
Pak K, Junga Z, Mertz A, Singla M. The Patterns and Associated Cost of Serologic Testing for Helicobacter pylori in the U.S. Military Health System. Mil Med. 2020 Sep 18;185(9-10):e1417-e1419. doi: 10.1093/milmed/usaa141.