Reliable detection of acute Helicobacter pylori infections remains problematic.
The high prevalence of false-positive non-invasive tests in low H pylori prevalence populations makes identification of acute and transient infections difficult.
Dr David Graham and colleagues from the USA explored the use of serum pepsinogens for diagnosis of acute infection.
The team compared those findings to a group of children with presumed acute infections.
The infections were defined as a positive urea breath test and negative immunoglobulin G serology.
| The frequency of a positive test was 17% at week 1|
The researchers examined the pattern and calculated cut-off values of pepsinogen levels in 18 adult volunteers with known acute H pylori infection.
The team assessed sera from 9 symptomatic children with presumed acute H pylori infection.
A matched control group of 9 children who did not meet criteria for acute H pylori infection were included.
In acute infection, both pepsinogens I and II levels increased following H pylori infection reaching a peak by 2 weeks post-infection.
The frequency of a positive test was 17%, 71%, and 94% at week 1, 2, and 4 post-infection, respectively.
Only 1 child with presumed acute H pylori infection had an elevated serum pepsinogens I and one had an elevated pepsinogens II.
The team found that 5 of the children had follow-up urea breath tests and 4 were negative consistent with the diagnosis of false-positive urea breath test.
H pylori infection was confirmed in the child with an elevated pepsinogens I level.
Dr Graham's team concluded, “These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result.”
“This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter.”
“It appears that most H pylori infections are diagnosed on the basis of false-positive tests, and pepsinogen levels are possible candidates as the confirmatory test.”