The specificity of bienzyme system for glucose sensing wasaddressed using other solutions as control samples (including uricacid, citric acid, glycine, glutamic acid, lactose, saccharose and bovine serum albumin), no detectable color responses were found when control samples were added to the substrate zones with the concentration as high as 0.1 M. The biosensors have good specificity due to the specificity of enzyme catalysis. As a result, the glucose biosensor could be used directly for detection in human serum samples.