Feasibility of gentamicin measurement in icteric sera by the Syva EMIT system

Area of Science:

• Clinical Chemistry
• Pharmacology
• Analytical Toxicology

Background:

• Accurate serum gentamicin levels are crucial for effective therapeutic drug monitoring.
• Potential interfering substances in patient samples can affect immunoassay accuracy.
• Bilirubin is a common endogenous substance that may interfere with various diagnostic assays.

Purpose of the Study:

• To evaluate the effect of varying total serum bilirubin concentrations on the accuracy of gentamicin quantification.
• To assess the reliability of the Syva EMIT system for gentamicin measurement in the presence of hyperbilirubinemia.

Main Methods:

• Serum samples were spiked with known concentrations of gentamicin (up to 14 mug/ml).
• Total serum bilirubin was added to these samples at concentrations up to 45 mg/dL.
• Gentamicin concentrations were measured using the Syva EMIT system, and results were compared to control samples without added bilirubin.

Main Results:

• Total serum bilirubin concentrations up to 45 mg/dL did not produce a significant bias in serum gentamicin measurements.
• The Syva EMIT system demonstrated robust performance across the tested range of bilirubin and gentamicin concentrations.

Conclusions:

• Hyperbilirubinemia, within the tested range, does not significantly interfere with serum gentamicin assays performed on the Syva EMIT system.
• The findings support the continued use of the Syva EMIT system for monitoring gentamicin therapy in patients with elevated bilirubin levels.