Evaluation and analysis of three methods of occult blood test

Abstract:

Objective：To evaluate hemoglobin monoclonal antibody immune colloidal gold method，hemoglobin and transferrin com－bined immunoassay，pyramidon chemical method for occult blood detection and to identify occult blood detection method consistent with clinical practice. Methods：Hemoglobin solutions of different concentrations were prepared，and the minimum detection limit and the highest test concentration of the three methods were checked. The specificity of these threeoccult blood testing methods was eval－uated with five kinds of animal blood. Feces and gastric juice specimens of hospitalized patientswere collected for three kinds of meth－ods of occult blood test. With endoscopy as the gold standard，the sensitivity，specificity，negative and positive likelihood ratio，and Youden index clinical coincidence rate were calculated. Results：Examination area of Kaichuang and Oritent was 200 ng/mL to 10 mg/mL，and 300 ng/mL to 2.5 mg/mL，respectively. The minimum detection limit ofpyramidon chemical method and combined immunoassaywas 2 500 ng/mL and 10 ng/mL. The clinicalcoincidence rates of Kaichuang，Oritent，pyramidon chemical method，combined immunoas－say in feces and gastric juice were respectively 96.0%，95.8%，79.5%，97.5% and 92.9%，92.9%，94.6%，90.2%. There were obvious differences in fecal occult blood test results between the four groups（P=0.000），but no difference was observed in the gastric occult blood detection results between groups（P=0.083）. Conclusion：For fecesoccult blood test，combined immunoassay is superior to hemoglobin immunization，hemoglobin immune method is better than the chemical method.For occult blood detection of gastric juice specimens，there is no significant difference among the three methods.