粪便还原性物质检测方法的建立及其在临床隐血试验中的应用

Establishment of a fecal occult blood test method in detecting reducing substances of feces and its clinical application

目的建立检测粪便还原性物质的方法，减少假阴性对粪便隐血试验的影响，提高检出率。方法测量化学法（邻联甲苯胺）和免疫胶体金法的检测限；用蒸馏水做阴性对照，检测还原性物质对化学法和胶体金法的影响；建立粪便还原性物质检测方法并用于临床试验。结果化学法检测血红蛋白检测限为≥4．9mg／L，胶体金法为1．2mg／L～2500mg／L；维生素C针剂或片剂≥156．3mg／L化学法结果假阴性；酒石酸在≥5000mg／L、枸橼酸在≥2500mg／L时胶体金法出现假阳性；改良化学法使用0．1g／L的碘液和1．0g／L的淀粉溶液等体积混合，室温下pH6．6时，在维生素C浓度≤1000mg／L时不会出现化学法假阴性。294例住院病人临床标本中，化学法阳性56例，改良化学法阳性106例，胶体金法阳性40例。结论改良化学法可检测出还原性物质并消除其影响，可减少隐血试验化学法的假阳件率．

Objective To establish a method for detecting reducing substances, avoid false negative of fecal occult blood test and improve detection rate. Methods The detection limit of chemical method （ortho-tolidine） and immune colloidal gold method were measured by a series of distilled water diluted known concentration of Hb.As negative control with distilled water, study the impact of reducing substances on the chemical method and the immune colloidal gold method.Establish a method to detect reducing substances in feces and use for clinical fecal occult blood test.Results The detection limit of hemoglobin with the chemical method is≥4.9 mg/L, it is from1.2 mg/L to 2500 mg/L with the colloidal gold method. When vitamin C concentration of injections or tablets is ≥ 156.3 mg/L, the chemical method had the false negative. When tartaric acid concentration is ≥5000 mg/L or citrate concentration is ≥ 2500 mg/L, the colloidal gold can be false positive.Mixed the 0.1g/L iodine solution and 1.0 g/L starch solution with equal volume, at the ordinary temperature and pH 6.6, detecting the reducing substances, which is the improved chemical method, there have no false negative result when the vitamin C concentration is 〈 1000 mg/L. In the 294 clinical specimens, 56 were positive using the chemical method, 106 were positive using the improved chemical method and 40 were positive using the colloidal gold method.Conclusions The improved chemical method can detect the reducing substances and eliminate its interference, avoid the false negative in fecal occult＇blood test.