40 A LC-MS/MS Method for the Quantitation of Chlorhexidine in Pediatrics Less Than 2 Months of Age

Abstract

Background: Chlorhexidine gluconate (CHG) is a topical antiseptic widely utilized for daily bathing in pediatric and adult populations and has been shown to be effective in reducing healthcare-associated infections (HAIs). However, the Centers for Disease Control (CDC) recommends using it with caution in patients less than 2 months of age. However, as HAIs remain a signifcant problem in this patient population, a study is ongoing at our institution addressing these concerns. The clinical chemistry team was recruited to help characterize CHG levels for this population. Preliminary validation results are reported here. Methods: A LC-MS/MS method was developed to quantitate CHG plasma levels. Linearity was determined from linear regression analysis (n = 7) of plasma levels spiked at 500ng/mL and diluted to 5 ng/mL. Precision was assessed by replicate measurement (n = 5) of CHG in spiked patient pools across the concentration range of 10 to 500 ng/mL. Adult, medical intensive care unit (MICU), and neonatal intensive care unit (NICU) patient pools were created (n = 3) from discarded clinical specimens. Matrix effect was measured by spiking in CHG in the pool and recovery was subsequently measured at 5, 20 and 100 ng/mL. Results: The calibration curve showed excellent correlation between the concentration and signal response (r =.97). Preliminary assay imprecision (%CV) was assessed at CHG concentrations of 500, 200, 100, 20, and 10 ng/mL. The mean coeffcient of variation (%CV) using the LC-MS/MS method at 500, 200, 100, 20, and 10 ng/mL were 2.9%, 4.9%, 4.3%, 17.4%, and 59.4%, respectively. Randomly selected clinically discarded specimens also revealed high background CHG exposure (>50 ng/mL). Baseline adult, MICU, and NICU pools showed >20 ng/mL CHG levels. The adult, MICU, and NICU pools showed comparable recovery across the different types of pools. Average recovery (%) ranged 37%-41%, 31%-37%, and 80%-115% at 5, 20, and 100 ng/mL, respectively. Conclusion: We have developed a LC-MS/MS method that allows us to quantitate chlorhexidine in patients younger than 2 months. We also show that detectable levels were common in neonates less than 2 months old.