Comparison of [13C]urea blood test to [13C]urea breath test for the diagnosis of Helicobacter pylori

Abstract

Objective: It has been determined that the [13C]urea breath test (UBT) is a safe and effective way of detecting Helicobacter pylori (H. pylori) infection. Some individuals may have difficulty performing the exhalation component of the test, possibly due to age, or mental or physical compromise. Our aim was to determine if a commercially developed [13C]urea blood test could be utilized as a substitute for the UBT to detect H. pylori infection.

Methods: Patients who were referred by their physicians for UBT were offered study inclusion. Patients underwent baseline and 30-min UBT. A simultaneous blood sample of 3 cc was drawn into a heparinized vacutainer at the 30-min period of the UBT. [13C]urea levels in both blood and breath samples were analyzed using isotope ratio mass spectrometry. UBT > or = 6 delta per mil over baseline and urea blood tests > (-17 delta per mil) were considered positive.

Results: One hundred sixty-one patients (68 men/93 women) with average age of 47.0 +/- 14.2 yr were tested. Agreement between breath and blood test results occurred in 153/161 (95%) cases. Using the UBT as the diagnostic standard, the urea blood test resulted in 44 true positive, 109 true negative, four false positive, and four false negative results, giving a sensitivity of 92%, specificity of 96%, positive predictive value of 92%, and negative predictive value of 96%.

Conclusions: The urea blood test was found to be comparable to the urea breath test in the detection of H. pylori infection. The urea blood test will be accurate in the diagnosis of active H. pylori infection.