Interference of new penicillins and cephalosporins with urine glucose monitoring tests.

The possibility that three new penicillins (mezlocillin, pipericillin, and azlocillin) and two new cephalosporins (ceftazidime and cefoperazone) might give false positive urine glucose testing results was studied. High and low concentrations of antibiotics were dissolved in urine and tested with Clinitest (Ames Division, Miles Laboratories, Elkhart, Indiana) and Tes-Tape (Eli Lilly and Company, Indianapolis, Indiana) at four different concentrations of glucose. None of the antibiotics interfered with the accuracy of Tes-Tape readings. All antibiotics interfered with Clinitest readings; the greatest interference was noted at high concentrations of antibiotics and low concentrations of glucose, and with the two cephalosporins. A summary of all reported cephalosporin interactions with Clinitest urine glucose testing is included.