SIMPLE C-13-UREA BREATH TEST WITH INFRARED SPECTROPHOTOMETER

When mass spectrophotometric analysis is used for the C-13-urea breath test to assess H. pylori infection, it is costly, complicated, and ti me-consuming. To overcome these disadvantages, we utilized an infrared spectrophotometer as a substitute for the mass spectrophotometer. A t otal of 153 patients (181 tests) analyzed with peptic ulcers or non-ul cer dyspepsia were investigated. Breath samples were collected 15 min after ingestion of C-13-urea (100 mg in 30 mi water). An infrared spec trophotometer was used to determine the concentration of (CO2)-C-13 in the expirate. The (CO2)-C-13/(CO2)-C-12 ratio was also measured by ma ss spectrophotometry to compare results with those of infra-red spectr ophotometric analysis. Direct detection of N. pylori was qualified in biopsy specimens. Of the 181 biopsies, 138 were positive for H. pylori infection and 43 were negative. With the urea breath test, the mean v alue in the positive group was significantly higher than that in the n egative group (0.062 +/- 0.044 vs 0.011 +/- 0.014, respectively). The cut-off level, 0.01, was determined as Delta(13)C atom %. The sensitiv ity of infra-red spectrophotometry was 97.8% (135/138) and specificity was 74.4% (32/43). There was an extremely high coefficient of correla tion (r = 0.996) between mass and infra-red photometric analysis. Infr a-red spectrometry appears to have great potential not only for diagno sing H. pylori infection but also for assessing treatment results. Its advantages include technical simplicity, cost-effectiveness, and high accuracy.