The Potential Role of the Rapid Urease Test with the Sweeping Method in the Gray Zone of the Urea Breath Test after Eradication.

Background/aims: Although the urea breath test (UBT) is widely used as a representative monitoring test after eradication, false-negative results can occur because of the gray zone related to its cutoff value. This study aimed to compare the diagnostic performances of the rapid urease test (RUT), the RUT with sweeping method, and the UBT, and to investigate the role of the sweeping method in the gray zone of UBT values.

Methods: We retrospectively reviewed 216 patients who received standard first-line eradication treatments (n=216). All participants underwent to testing using the sweeping method and UBT on the same day. The sensitivity, specificity, and accuracy were analyzed to compare the two methods.

Results: The sensitivity (0.537 vs 0.806, p=0.002) and accuracy (0.843 vs 0.870, p=0.026) of the UBT were inferior to those of the sweeping method. A total of 31 individuals tested positive for according to the UBT, whereas 54 individuals tested positive according to the sweeping method. In the group for which the gold standard definition indicated positivity but UBT results were negative (n=31), all individuals had a UBT value under 2.5‰. In the multivariate logistic regression model, a UBT value of 1.4‰ to 2.5‰ increased the risk of false-negative results by 6.5 times (odds ratio, 6.5; 95% confidence interval, 2.077 to 20.288; p=0.001).

Conclusions: After eradication, false-negative results can occur for individuals undergoing the UBT, primarily for values below the UBT cutoff. The RUT with the sweeping method can potentially help detect in the gray zone of the UBT, improving diagnostic accuracy.