López Peñas D, Naranjo Rodríguez A, Muñoz Molinero J, Rodríguez López F, Gálvez Calderón C, Chicano Gallardo M, López Rubio F, Miño Fugarolas G
Unidad Clínica de Aparato Digestivo, Hospital Universitario Reina Sofía, Córdoba.
Gastroenterol Hepatol. 2001 Jan;24(1):5-8.
The rapid urease test is the most commonly used test in the diagnosis of Helicobacter pylori infection in patients with upper gastrointestinal hemorrhage. However, some studies have suggested that results of this test are frequently false negative when blood is present. An effective new enzyme immunoassay for determining H. pylori antigens in stools has recently begun to be used.
To determine the efficacy of the H. pylori stool antigen test (HpSAT) in patients with upper gastrointestinal hemorrhage.
Thirty-two patients with upper gastrointestinal hemorrhage were prospectively studied from November 1998 to April 1999. In all patients the following tests were performed in the first 72 hours after onset of bleeding and 24 hours after hospital admission: upper gastrointestinal endoscopy, biopsy samples for the rapid urease test and histological study, blood samples for serology, stool samples for HpSAT, and the 13C urea breath test. Criteria for infection was a positive result in at least two of the four diagnostic techniques, except in the case of HpSAT. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.
Of the 32 patients, 23 (71.8%) were infected. The results of four HpSAT (12.5%) were negative and 28 were positive (87.5%). HpSAT showed high sensitivity (95.6%) but low specificity (33.3%). The PPV and NPV were 78.5% and 75% respectively. Of the 32 HpSAT, 25 (78.1) were performed in melenic stools: 22 were positive and 3 were negative. Seventy-five percent of negative HpSAT and 78.5% of positive HpSAT corresponded to melenic stools.
HpSAT is a rapid, non-invasive technique that does not appear to be influenced by the presence of blood. Consequently, it can be applied in patients with upper gastrointestinal hemorrhage. The rapid urease test showed high sensitivity, specificity and PPV and should remain the first-line test in patients with upper gastrointestinal hemorrhage. HpSAT is appropriate as a second-line technique and is useful when the rapid urease test is negative and infection is strongly suspected, when no samples for the rapid urease test have been taken and when endoscopy cannot be performed. The result obtained in the present study should be confirmed in future studies with larger samples.
快速尿素酶试验是上消化道出血患者幽门螺杆菌感染诊断中最常用的检测方法。然而，一些研究表明，当存在血液时，该检测结果常为假阴性。一种用于测定粪便中幽门螺杆菌抗原的新型有效酶免疫测定法最近已开始应用。
确定幽门螺杆菌粪便抗原检测（HpSAT）在上消化道出血患者中的有效性。
对1998年11月至1999年4月期间32例上消化道出血患者进行前瞻性研究。所有患者在出血发作后的前72小时内及入院后24小时进行以下检测：上消化道内镜检查、用于快速尿素酶试验和组织学研究的活检样本、用于血清学检测的血液样本、用于HpSAT检测的粪便样本以及13C尿素呼气试验。感染标准为四种诊断技术中至少两种结果为阳性，但HpSAT除外。计算敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）。
32例患者中，23例（71.8%）感染。4例HpSAT结果（12.5%）为阴性，28例为阳性（87.5%）。HpSAT显示出高敏感性（95.6%）但低特异性（33.3%）。PPV和NPV分别为78.5%和75%。32例HpSAT检测中，25例（78.1%）在柏油样便中进行：22例为阳性，3例为阴性。75%的阴性HpSAT和78.5%的阳性HpSAT对应柏油样便。
HpSAT是一种快速、非侵入性技术，似乎不受血液存在的影响。因此，它可应用于上消化道出血患者。快速尿素酶试验显示出高敏感性、特异性和PPV，应仍然是上消化道出血患者的一线检测方法。HpSAT适合作为二线技术，当快速尿素酶试验为阴性且强烈怀疑感染时、未采集快速尿素酶试验样本时以及无法进行内镜检查时，它很有用。本研究获得的结果应在未来更大样本的研究中得到证实。
