Comparison of testing methods for H. pylori infection

Table 1: Comparison of testing methods for H. pylori infection [37,45-47].

Test	Description of Test	Sensitivity	Specificity	Advantages	Limitations
Rapid urease testing	Gastric biopsies are incubated with urea and the H. pylori urease enzyme converts it to ammonia and bicarbonate. The test detects an increase in pH.	85-90%	98-100%	Rapid testing (5 mins-24 hours depending on kit) Inexpensive	Requires endoscopy to obtain samples. Sensitivity is dependent on the number of bacteria present, thus limited by H2-receptor antagonists, PPIs, antibiotics, and presence of blood.
Histology	Hematoxylin and eosin (H&E) staining is typically sufficient for detection of infection but immunohistochemical stain has greater sensitivity and specificity. A variety of other staining methods can be employed if there is severe gastritis but no infection initially detected.	82-95%	99-100%	Allows for concurrent evaluation for inflammation, metaplasia, and malignancy.	Requires endoscopy to obtain samples. Accuracy is dependent on size and site of biopsies, histological staining techniques, use of PPIs, use of antibiotics, and interpretation by pathologist. Expensive Requirement for trained personnel for sample processing and interpretation. Possible false positive results if other H. pylori species are present.
Culture	Requires special transport medium (e.g. Stuart’s), growth medium (e.g. Pylori agar) and incubation environment (microaerobic environment) for 5-7 days.	70-80%	100%	Determination of antibiotic susceptibility.	Requires endoscopy to obtain samples. Can take a week to detect infection. Test affected by quality of specimens, transportation method, exposure to aerobic conditions, and growth conditions. Affected by use of H2-receptor antagonists, PPIs, and antibiotics. Expensive
Polymerase chain reaction (PCR)	Several genes can be used for DNA amplification.	> 95%	> 95%	Uses a variety of samples: gastric juice and biopsy. Determine mutations causing resistance. Rapid and accurate	Expensive Requires specialized equipment and reagents.
Antibody testing	Detection of IgG antibodies against H. pylori using enzyme-linked immunosorbent assay (ELISA) and latex agglutination.	76-84%	79-90%	Least expensive of all tests. Rapid Readily available	Remains positive for years even after eradication of the infection. Influenced by the prevalence of the infection. Requires local validation of reagents. Not appropriate for detection of active infection or confirmation of eradication.
Urea breath test (UBT)	Patient ingests non-radioactive isotope ¹³C or radioactive isotope ¹⁴C labeled urea and the resultant CO₂ is quantified.	> 95%	> 95%	Noninvasive and simple Post treatment testing for eradication. Reproducible	Exposure to radiation with ¹⁴C, thus avoided in pregnancy and children. Sensitivity is dependent on the number of bacteria present thus limited by PPIs, antibiotics, and blood. Expensive Equipment requirements
Fecal antigen test	Detects H. pylori antigen in stool using either enzyme immunoassay (EIA) or immunochromatography assay (ICA) and antibodies.	94%	97%	Noninvasive Screen and determine eradication of infection. Inexpensive	Sensitivity is dependent on the number of bacteria present, thus limited by PPIs, antibiotics, and blood. Availability Cumbersome for patient to provide sample.