Improved performance of a rapid office-based stool test for detection of Helicobacter pylori in children before and after therapy.
A modified version of a rapid office based one-step monoclonal immunoassay for detection of Helicobacter pylori antigen in stool samples from children was evaluated against biopsy specimen-based methods and compared to a monoclonal enzyme immunoassay using the same antigen. Blinded stool samples from 185 children (0.3 to 18.2 years) were investigated at the time of upper endoscopy prior to anti-H. pylori therapy; 62 children were H. pylori infected and 123 noninfected according to predefined reference standards. Samples obtained 6 to 8 weeks after anti-H. pylori therapy were available from 58 children (3.8 to 17.7 years) and were compared to results of the [(13)C]urea breath test (14/58 were positive). The rapid stool tests were performed by two independent readers. Of 243 rapid tests performed, 1 (0.4%) was invalid for technical reasons. Equivocal results (very weak line) were reported 16 times by reader 1 and 27 times by reader 2. When equivocal results were considered positive, the two observers agreed on 76 positive and 160 negative results and disagreed on 7 samples (2.9%). The sensitivity was 90.8% for reader 1 and 85.5% for reader 2, and the specificity was 91.0% and 93.4%, respectively. The monoclonal enzyme immunoassay revealed a sensitivity and specificity of 94.7% and 97.6%, respectively. The modified chromatographic immunoassay is a good alternative in settings or situations when the monoclonal enzyme immunoassay or the [(13)C]urea breath test are not available or feasible. In order to improve sensitivity, very weak lines should be considered positive test results.
Dr von Haunersches Kinderspital, Ludwig-Maximilians-University Munich, Lindwurmstrasse 4, 80337 Munich, Germany.
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C
Prell
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Osterrieder
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C
Lottspeich
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A
Schwarzer
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Rüssmann
G
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Ossiander
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Koletzko
D000293:Adolescent; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis*; D001944:Breath Tests; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000382:microbiology*; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007223:Infant; D015588:Observer Variation; D012680:Sensitivity and Specificity; D013997:Time Factors; D014508:Urea / Q000032:analysis
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D014508:Urea