Effect of intravenous glucose on serum glucose determinations

Hyperglycemia is frequently seen in hospitalized nondiabetic patients receiving intravenous glucose solutions. As no standard method of interpreting the serum glucose value has been defined in patients receiving intravenous glucose, we have attempted to determine if any correlation can be made. It was found that with a 5% dextrose in water infusion at 100 ml/hr, the mean change in serum glucose was 9 mg/100 ml above the fasting serum glucose; with a 5% dextrose in water at 200 ml/hr, the mean serum glucose rose 24 mg/100 ml above the fasting serum glucose obtained in the arm opposite the intravenous infusion. It was thus determined that a serum glucose level greater than 20 mg/100 ml above the fasting serum glucose level in an individual with a 5% glucose in water infusion at 100 ml/hr, or 42 mg/100 ml above the fasting serum glucose in an individual with a 5% glucose in water infusion at 200 ml/hr, which are 3 SD above the mean glucose, should be early evidence for mild subclinical glucose intolerance.