Measured versus estimated aluminum content of parenteral nutrient solutions

A study was conducted to directly measure the aluminum concentration in a select number of parenteral nutrient (PN) solutions and to compare this value with the calculated dose using the concentrations reported by the manufacturer.

Fifty 2.5-mL samples were prepared for analysis and were obtained from PN solutions prepared for adult and pediatric/neonatal patients. Intravenous large-volume parenterals were used as controls. Samples were sent to two different reference laboratories. Batch 1 included 26 samples, 22 from PN solutions, 1 control, and 3 paired (duplicate) samples selected from the 22 PN bags. Because 8 of the samples were lost to analysis, a second batch of samples was included. Batch 2 consisted of 24 samples from 4 PN solutions and 2 controls. Batch 2 was composed of four aliquots from each solution that were divided equally and sent to the two laboratories.

Twenty-three values were used in the statistical analysis. The results showed that only two of the adult PN solutions equaled or exceeded the threshold set by the Food and Drug Administration (FDA) for measured aluminum exposure. The measured concentration of aluminum for all six of the pediatric and neonatal solutions met or exceeded the FDA threshold; however, this value was much lower than what had been estimated using the labeled aluminum concentration at expiry.

In PN solutions expected to have a moderately high concentration of aluminum, the measured amount of aluminum was far less than the amount that would be estimated by calculation using the labeled concentrations of aluminum in each of the ingredients.