Routine glucose determination in serum by use of an immobilized glucose dehydrogenase nylon-tube reactor

We report a method for immobilizing glucose dehydrogenase on the inside surface of nylon tubes to produce an immobilized-enzyme nylon-tube reactor. The glucose dehydrogenase reactor is integrated into the flow system of a continuous-flow analyzer to facilitate routine analysis of serum glucose at 50 samples/h. We compared results with those by the reference hexokinase/glucose-6-phosphate dehydrogenase solution method. The coefficient of correlation was r = 0.996. A glucose dehydrogenase reactor made starting with 1 mg (250 U) of enzyme was stable during eight weeks of continuous use, that is, for nearly 3500 tests. This reduced the cost of the assay by at least 50-fold, compared with that for a commercial glucose dehydrogenase test pack method.