We previously reported the development and the possible application of reverse transcription-polymerase chain reaction (RT-PCR) assay for the detection of H. pylori in gastric mucosal biopsy specimens. In this communication, the application of this assay was assessed by comparing its results from 79 gastric biopsy specimens obtained from 68 patients with the more traditional [13C]urea breath test. When the amplified products were examined, the specificity and sensitivity of this RT-PCR assay were 100% and 47% on agarose gels and 80% and 91% by Southern hybridization, respectively. The specificity and sensitivity of urea breath test were 91% and 96% and were generally superior to RT-PCR (negative predictive value of 94% for UBT and 59-76% for RT-PCR). Although our RT-PCR results compare favorably with other PCR assays applied to gastric biopsy specimens for the detection of H. pylori, the use of this method did not add significantly to currently available noninvasive diagnostic methods.