title: Helicobacter pylori infection in asymptomatic children: comparison of diagnostic tests.
abstract: BACKGROUND
  Childhood is known to be a major risk period for acquiring Helicobacter pylori infection. Studies of the epidemiology of H. pylori infection depend on the validity of the diagnostic tools used to detect the infection in the pediatric setting. This study aims to conduct a combination of diagnostic tests on the same children, evaluate the sensitivity and the specificity of IgG antibody testing compared with the 13C-urea breath test, and examine the variability in the prevalence of H. pylori infection in asymptomatic children based on the use of different diagnostic tests.
  
  
  METHODS
  13C-urea breath test (13C-UBT), whole blood FlexSure (systemic antibodies), and OraSure (salivary antibodies) tests were conducted on 287 asymptomatic children (151 boys, 136 girls; ages 2-18 years). The three tests were conducted on each child during the same day. The prevalence was calculated using each test independently.
  
  
  RESULTS
  H. pylori infection was detected in 32%, 22%, or 18% of the studied children, based on UBT, OraSure, or FlexSure, respectively. A total of 103 children tested positive for any one test (92 on UBT, 8 on FlexSure, 3 on OraSure), giving a prevalence of 35% based on the "parallel" method. Only 39 children tested positive in all three tests, giving a prevalence of 14% based on the "serial" method. Using the UBT as the gold standard, the sensitivity of FlexSure and OraSure were 48% and 65%, respectively, and the specificity of both tests was greater than 95%. When we applied the parallel method, the sensitivity and specificity of the combined antibody tests (FlexSure + OraSure) compared to the UBT were 71% and 95%, respectively.
  
  
  CONCLUSIONS
  Among asymptomatic children, there is a wide variation in the prevalence of H. pylori infection based on the diagnostic test used. The study shows that antibody assays are less suitable than the UBT. However, under certain conditions, the IgG assays (combined systemic, salivary, or both) are less expensive alternative tools to the UBT for epidemiological studies in children.
authors.affiliation: Department of Medicine and Division of Molecular Virology, Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Malaty
authors.forename: N D
authors.initials: ND
authors.lastname: Logan
authors.forename: D Y
authors.initials: DY
authors.lastname: Graham
authors.forename: J E
authors.initials: JE
authors.lastname: Ramchatesingh
authors.forename: S G
authors.initials: SG
authors.lastname: Reddy
mesh_terms: D000293:Adolescent; D000906:Antibodies / Q000032:analysis; D001944:Breath Tests; D002648:Child; D002675:Child, Preschool; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000453:epidemiology; D016480:Helicobacter pylori; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood*; D008297:Male; D011237:Predictive Value of Tests; D015995:Prevalence; D012463:Saliva / Q000276:immunology*; D012680:Sensitivity and Specificity; D014508:Urea / Q000032:analysis
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D014508:Urea