Novel Diagnostic Tests to Detect Helicobacter pylori Infection: A Pediatric Perspective
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Wed Sep
Helicobacter pylori infection: A pediatric perspective
John D Snyder
Sander Veldhuyzen van Zanten
JD Snyder, S Veldhuyzen van Zanten. Novel diagnostic tests to detect Helicobacter pylori infection: A pediatric perspective. Can J Gastroenterol 1999;13(7):585-589. Because of the widespread problem of Helicobacter pylori infections, there is an increased need for rapid, reliable and inexpensive diagnostic tests. Five recently developed tests that offer potential advantages because they are less invasive or permit easier acquisition of samples than available tests are assessed. The tests assessed are whole blood, saliva and urine assays that measure systemic antibody response to H pylori, stool tests that measure H pylori antigens and string tests that recover H pylori organisms.
Children; Enzyme-linked immunosorbant assay; Helicobacter pylori; Serological testing; Urease
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CANADIAN HELICOBACTER CONSENSUS CONFERENCE ON PEDIATRIC ISSUES
Helicobacter pylori is one of the most common bacterial
in
fections in humans, and has been found in differing
rates in persons of all age groups, nationalities and
socioeconomic classes (
1
). Because the role of H pylori in human disease
continues to be explored, there is an increased need for rapid,
reliable and inexpensive diagnostic tests (
2,3
). The most
commonly used standard tests are listed in Table 1. To date, the
only test that can detect infection and disease activity is
endoscopy with biopsy, which is invasive and expensive.
Five recently developed tests that offer potential
advantages because they are less invasive or permit easier
acquisition of samples are assessed. These tests are whole blood,
saliva and urine assays that measure systemic antibody
response to H pylori, stool tests that measure H pylori antigens
and string tests that use methodology less invasive than upper
gastrointestinal endoscopy to recover H pylori organisms.
The tests are compared with current standard tests and
Nouveaux tests diagnostiques pour déceler
une infection à Helicobacter pylori : une
perspective pédiatrique
RÉSUMÉ : Étant donné l’importance du problème des infections à
Helicobacter pylori, on a de plus en plus besoin de tests diagnostiques
rapides, fiables et peu coûteux. On a évalué cinq tests récemment mis au
point et qui présentent des avantages potentiels parce qu’ils sont moins
effractifs ou qu’ils permettent de recueillir des échantillons plus facilement
que les tests disponibles. Les tests évalués sont des dosages de sang entier,
d’urine et de salive qui mesurent la réponse systémique des anticorps à H.
pylori, des examens de selles qui mesurent les antigènes de H. pylori et des
épreuves du fil qui recueillent H. pylori.
criteria for optimal tests. The criteria are non- or minimally
invasive nature; high sensitivity, specificity, and positive
and negative predictive values in diagnosing infection and
assessing disease activity and effectiveness of therapy;
convenience, including ease of acquisition of samples and rapid
determination of results; and low cost.
WHOLE BLOOD ANTIBODY TESTS
Background: Whole blood antibody tests are based on the
fact that systemic antibodies to H pylori are found in whole
blood, making testing possible in a primary care setting
(
2-9
). Whole blood tests have several important potential
advantages compared with standard serological tests; the
samples are easier to obtain, testing can be done in an office
setting and the results can be available within 10 mins. In
addition, the cost is projected to be less than that for the
standard serological tests.
1University of California San Francisco Medical Center, San Francisco, California, USA; 2Queen Elizabeth II Health Sciences Centre,
Halifax, Nova Scotia
Correspondence: Dr John D Snyder, Department of Pediatrics, Box 0136, MU East 413, University of California
San Francisco Medical Center, 500 Parnassus Avenue, San Francisco, California 94143, USA. Telephone 415-476-5892, fax 415-476-1343,
e-mail
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Snyder and Veldhuyzen van Zanten
Methodology: Whole blood samples are obtained by finger
prick yielding one to two drops of blood that are placed
directly onto a test slide. The most effective assays measure
immunoglobulin (Ig) G antibodies to highly specific H pylori
antigens using ELISA techniques (
2,3
). Colorimetric results
can usually be read in less than 10 mins. Several commercial
kits are available (Table 2).
Comparison with serological assays: Most of the studies
evaluating whole blood antibody tests have been reported in
abstract form and have used one standard test as the ‘gold
standard’ to diagnose H pylori (
4-9
). Individual tests have not
been validated formally by multiple investigators or evaluated
in an office setting. Evaluation of these tests in pediatric
populations is limited; preliminary data indicate that their
performance is likely to be similar to that in adults (8). The
sensitivity, specificity, and positive and negative p (...truncated)