Objective To explore colloidal gold method used to detect fecal occult blood tests(FOB)detection capability and establish the laboratory standard operation of detecting FOB limit of blank(LOB),limit of detection (LOD)and quantifica-tion limit (LOQ)according to the CLSI document《Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures;Approved Guideline-Second Edition》(EP17-A2),in order to reduce the false negative rate of the weakly positive samples,and to provide a way of quantitative detection for qualitative detection of colloidal gold method.Methods Detected series of solution of hemoglobin made of dissolved fresh whole blood with the ELISA kit of human free hemoglobin,and es-tablished the standard curve of detection of FOB with colloidal gold method.Detected the blank samples and a series of low concentration samples with the colloidal gold test strip of FOB and measured the color bands by the Nato Checker710.The quantitative results obtained were statistically analysised by SPSS 1 9.0 and calculated blank limit,detection limit and quanti-fication limit.Results The LOB,LOD and LOD were 99.01,340.48 and 354.9 ng/ml according to the methods in CLSI EP1 7-A2 ducument.Conclusion The detection limits established by CLSI EP1 7-A2 document was more scientific in j udge-ment positive or negative to FOB than which used naked eye and can meet the clinical laboratory and clinical doctor require-ment better.Clinical laboratories should be strictly in detection limits of reagents in order to ensure their effectiveness,and should be generaly to other tests based on colloidal gold method.