The "eyetone" blood glucose reflectance colorimeter evaluated for in vitro and in vivo accuracy and clinical efficacy.

We evaluated the performance of a blood glucose reflectance colorimeter ("Eyetone," Ames Co.) for accuracy and precision with use of "Dextrostix" (Ames Co.) glucose oxidase reagent strips for blood samples with known and unknown concentrations of glucose covering the usual range of neonatal blood glucose (200-800 mg/L). The meter was calibrated and tested by research nurses and one clinical chemist. Five unknowns were tested for accuracy and precision (56-92 determinations per unknown) and compared with Beckman Astra values (plasma and calculated whole blood). Eyetone/Dextrostix values differed (gave lower values) from the calculated whole-blood values only at concentrations less than 300 mg/L. On 258 clinical specimens from newborn infants, Eyetone/Dextrostix values were not different from calculated whole-blood values (p less than 0.05, r = 0.80). Operator training to develop a consistent procedure was the most critical factor in achieving accurate and precise results.