Pajares-García J M
University Hospital Princesa, Autonoma University, Madrid, Spain.
Ital J Gastroenterol Hepatol. 1998 Oct;30 Suppl 3:S320-3.
The methods which require endoscopy for the examination of the gastric mucosa are called invasive (direct) methods. Several tests can be performed on the gastric mucosa obtained by endoscopy: Rapid urease test, histology, smear (cytology), culture and polymerase chain reaction. A combination of at least two tests with high sensitivity and specificity is recommended for clinical trials, and, when possible, for clinical management of patients. In clinical practice the invasive methods should be carried out only in those patients to be treated with eradication regimes. All invasive methods rely on gastric biopsy samples. Therefore, the specimens should be taken under optimal conditions. Several factors guide the site and the number of biopsy specimens for identification of Helicobacter pylori infection. In pre-treatment diagnosis, the biopsies should be taken from the distal antrum (2 cm from the pylorus). The number required depends on the diagnostic method used: in Helicobacter pylori eradicated patients the same number of biopsies for histology and culture should be taken from the antrum and corpus. The sensitivity and specificity of the Rapid urease test varies from 80-90% the results are known very quickly and the cost is very low. The maximal accuracy of histology is obtained with: an optimal specimen processing, an adequate staining and an experienced observer. This method of biopsy processing facilitates the identification of Helicobacter pylori which is commonly located on the superficial and foveolar epithelium. Sensitivity depends on the observer's experience and the extent of biopsy sampling. In general, the histological method has a sensitivity and specificity of 90-95%. In patients treated by proton pump inhibitors, antibiotics or bismuth salts two-four weeks prior to biopsy, the bacteria may be restricted to the corpus or fundus. Culture is strictly indicated in patients after failure of two or more eradication regimens to test for susceptibility and resistence. Specificity is 100% and sensitivity depends on the experience and interest of the microbiologist. The indication of polymerase chain reaction is only for research, specially, in molecular epidemiology and for fingerprinting.
需要通过内镜检查胃黏膜的方法被称为侵入性（直接）方法。可对通过内镜获取的胃黏膜进行多项检测：快速尿素酶试验、组织学检查、涂片（细胞学）、培养及聚合酶链反应。对于临床试验以及在可能的情况下对于患者的临床管理，建议至少结合两种具有高敏感性和特异性的检测方法。在临床实践中，侵入性方法仅应在那些接受根除治疗方案的患者中进行。所有侵入性方法都依赖于胃活检样本。因此，样本应在最佳条件下采集。有几个因素指导着用于鉴定幽门螺杆菌感染的活检样本的部位和数量。在治疗前诊断中，活检应取自胃窦远端（距幽门2厘米处）。所需数量取决于所使用的诊断方法：在幽门螺杆菌已被根除的患者中，应从胃窦和胃体采集相同数量的用于组织学和培养的活检样本。快速尿素酶试验的敏感性和特异性在80%至90%之间，结果很快就能得知，且成本非常低。组织学检查的最大准确性可通过以下方式获得：最佳的样本处理、适当的染色以及经验丰富的观察者。这种活检处理方法有助于识别通常位于浅表和小凹上皮的幽门螺杆菌。敏感性取决于观察者的经验和活检采样的范围。一般来说，组织学方法的敏感性和特异性为90%至95%。在活检前两到四周接受质子泵抑制剂、抗生素或铋盐治疗的患者中，细菌可能局限于胃体或胃底。在两种或更多根除方案失败后，严格建议对患者进行培养以检测药敏性和耐药性。特异性为100%，敏感性取决于微生物学家的经验和关注度。聚合酶链反应仅用于研究，特别是在分子流行病学和指纹识别方面。
