Comparison of gentamicin assays

Area of Science:

• Clinical Chemistry
• Pharmacology
• Analytical Chemistry

Background:

• Gentamicin therapy requires precise monitoring to ensure efficacy and minimize toxicity.
• Radioimmunoassay (RIA) is an established method for measuring gentamicin levels.
• Enzyme multiplied immunoassay technique (EMIT) is a newer immunoassay method.

Purpose of the Study:

• To compare the reliability of a newly developed enzyme multiplied immunoassay technique (EMIT) for gentamicin with a radioimmunoassay (RIA) technique.
• To evaluate the accuracy, precision, and correlation between EMIT and RIA for gentamicin measurement.

Main Methods:

• A split sample comparison was performed on 86 serum samples from 35 patients.
• Gentamicin levels were measured using both EMIT (Gilford System 4) and RIA (Abbott Auto Log Gamma Counter).
• Statistical analysis included correlation, slope, and intercept calculations.

Main Results:

• The EMIT and RIA methods showed good correlation (r = 0.954), with a slope of 0.952 and an intercept of 0.017.
• Within-run and between-run precision were comparable for both assay systems.
• Both methods demonstrated suitability for routine therapeutic monitoring of gentamicin.

Conclusions:

• The EMIT gentamicin assay is a reliable alternative to RIA for therapeutic drug monitoring.
• EMIT offers significant advantages in speed and simplicity over RIA.
• EMIT maintains comparable accuracy and precision to established RIA procedures.