Use of refractive index measurement for quality assurance of pediatric parenteral nutrient solutions

Use of refractive index measurements to assure accurate formulation of pediatric parenteral nutrient base solutions is described. The refractive indexes for various amino acid and dextrose concentrations were determined. An equation was derived to define the theoretical refractive index for combinations of amino acids and dextrose. Finally, a clinically acceptable range (deviation from theoretical) was determined. The actual refractive index for 300 pediatric parenteral nutrient solutions was compared with the calculated theoretical reading. The actual refractive index for all solutions was consistently predicted by the derived equation. Discussions with clinicians resulted in identification of an allowable range for these readings. All reading were within the identified range. The use of refractive index measurements is a valuable quality assurance tool for pediatric parenteral nutrient base formulations.