Measurement of the serum anti-H. pylori antibody titer is a noninvasive, inexpensive, and readily available method for detection of H. pylori infection. Histology, culture, polymerase chain reaction (PCR), and the rapid urease test all require biopsy and/or collection of specimens by endoscopy, an invasive technique that is not suitable for mass screening [9 (link), 10 (link)]. The urea breath test and stool antigen test are regarded as noninvasive tests, but the results of both methods are significantly affected by proton pump inhibitor therapy [11 (link)–13 (link)]. However, validated serology tests can be used even in patients being treated with proton pump inhibitors.
H. pylori strains possessing the cytotoxin-associated gene A (CagA) protein, a well-known virulence factor, cause more extensive inflammation and severe atrophy in gastric mucosa than nonproducers [14 (link), 15 (link)]. However, there is still controversy regarding the significance of CagA serology, especially in East Asia, where most strains of H. pylori are CagA producers [16 (link)–19 (link)]. Therefore, gastric cancer screening is usually performed using the H. pylori antibody titer alone, except in limited areas [20 (link)].
Burucoa et al. [21 (link)] investigated the accuracy of 29 different serological tests and reported positive and negative predictive values of 70% and 100%, respectively. In general, better performance in serological screening depends on the use of the appropriate antigens and adjustment of cut-off values [22 (link)]. These considerations are among the disadvantages of using serum H. pylori antibody as a screening test for gastric cancer. Another disadvantage of using H. pylori antibody is that serology alone presents a challenge in distinguishing past and current infections [23 (link)]. The use of serology to identify posteradicated cases is considered later in this review.
H. pylori strains possessing the cytotoxin-associated gene A (CagA) protein, a well-known virulence factor, cause more extensive inflammation and severe atrophy in gastric mucosa than nonproducers [14 (link), 15 (link)]. However, there is still controversy regarding the significance of CagA serology, especially in East Asia, where most strains of H. pylori are CagA producers [16 (link)–19 (link)]. Therefore, gastric cancer screening is usually performed using the H. pylori antibody titer alone, except in limited areas [20 (link)].
Burucoa et al. [21 (link)] investigated the accuracy of 29 different serological tests and reported positive and negative predictive values of 70% and 100%, respectively. In general, better performance in serological screening depends on the use of the appropriate antigens and adjustment of cut-off values [22 (link)]. These considerations are among the disadvantages of using serum H. pylori antibody as a screening test for gastric cancer. Another disadvantage of using H. pylori antibody is that serology alone presents a challenge in distinguishing past and current infections [23 (link)]. The use of serology to identify posteradicated cases is considered later in this review.
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