Peura D A, Pambianco D J, Dye K R, Lind C, Frierson H F, Hoffman S R, Combs M J, Guilfoyle E, Marshall B J
University of Virginia Health Sciences Center, Martha Jefferson Hospital, Charlottesville, USA.
Am J Gastroenterol. 1996 Feb;91(2):233-8.
The urea breath test diagnoses Helicobacter pylori infection of the stomach by identifying the urease enzyme activity of the bacterium. In this "microdose" version of the test, 1 microCi 14C-urea is given orally in a capsule. Our objectives were: 1) to evaluate a microdose 14C-urea breath test capsule in a gastroenterology outpatient setting, 2) to determine the diagnostic ranges of the 14C-urea breath test for HP-positive and HP-negative patients, 3) to define the sensitivity and specificity of the test, and 4) to see whether breath sample results changed when they were mailed to a remote site for analysis.
In a prospective blinded study, we breath-tested 200 fasted patients before elective outpatient endoscopy. At endoscopy, two gastric biopsy samples were taken and were examined for curved organisms; a third biopsy specimen was evaluated with a rapid urease test (CLOtest). Breath samples were mailed in aluminized balloons to a testing laboratory.
Using a single breath sample collected at 10 min, with > or = 200 dpm as positive, the breath test correctly classified 63 of 65 HP-positive patients (sensitivity 97%, CI 89-99%), and 128 of 135 HP-negative patients (specificity 95%, CI 90-98%). Radiation exposure from the test equated to natural background received in 1 day. No adverse events were caused by the breath test.
The 14C-urea capsule breath test (PYtest) is a convenient noninvasive test for the detection of gastric H. pylori infection. Accuracy is equivalent to invasive methods such as histology. Results can be obtained within 15 min if a counting instrument is nearby, or breath samples can be mailed to a testing laboratory for analysis.
尿素呼气试验通过检测幽门螺杆菌的脲酶活性来诊断胃部幽门螺杆菌感染。在这种“微量剂量”版本的试验中，口服一粒胶囊，其中含有1微居里的14C-尿素。我们的目的是：1）在胃肠病门诊环境中评估微量剂量14C-尿素呼气试验胶囊；2）确定14C-尿素呼气试验对幽门螺杆菌阳性和阴性患者的诊断范围；3）明确该试验的敏感性和特异性；4）观察将呼气样本邮寄至远程站点进行分析时，结果是否会发生变化。
在一项前瞻性盲法研究中，我们对200例择期门诊内镜检查前的空腹患者进行了呼气试验。在内镜检查时，采集两份胃活检样本，检查是否有弯曲菌属；第三份活检标本用快速尿素酶试验（CLOtest）进行评估。呼气样本装在镀铝气球中邮寄至检测实验室。
以10分钟时采集的单次呼气样本，≥200dpm为阳性，呼气试验正确分类了65例幽门螺杆菌阳性患者中的63例（敏感性97%，可信区间89%-99%），以及135例幽门螺杆菌阴性患者中的128例（特异性95%，可信区间90%-98%）。该试验所致的辐射暴露相当于1天内接受的自然本底辐射。呼气试验未引起不良事件。
14C-尿素胶囊呼气试验（PYtest）是一种方便的非侵入性检测胃部幽门螺杆菌感染的方法。准确性与组织学等侵入性方法相当。如果附近有计数仪器，15分钟内即可获得结果，或者呼气样本可邮寄至检测实验室进行分析。
