An anlysis of the 1977 College of American Pathologists (CAP) Comprehensive Chemistry Survey program for glucose measurements is presented. Based on average mean concentrations compared with all-method mean concentration, hexokinase methods are the most accurate. Glucose oxidase-oxygen rate methods demonstrate the best precision in interlaboratory comparison statistics. Neocuproine methods for glucose manifest unacceptable positive biases when compared with overall mean concentrations and other methods. Accuracy and precision indices for glucose measurements in urine are well below those obtained in serum. Again, redox methods, such as those based on neocuproine and ferricyanide, perform so poorly that they should be eliminated.