Vancomycin and Aminoglycoside Antibiotic Drug Concentration Measurement: Current Status in Clinical Laboratories in Korea

ABSTRACT

Background@#Therapeutic drug monitoring (TDM) is clinically recommended for vancomycin and aminoglycoside antibiotics owing to their narrow therapeutic range and nephrotoxicity at high concentrations in the blood. This study was conducted to investigate the current status of TDM of vancomycin and aminoglycosides in Korean clinical laboratories. @*Methods@#Ten organizations participated in this survey. Vancomycin, amikacin, gentamicin, and tobramycin were prepared in three samples of five or six different concentrations. Data from each institution were calculated for the mean, standard deviation, within-day, between-day, and within-laboratory precision. The results from each institution were compared in various ways. @*Results@#Six instruments from three manufacturers were used. Samples with the lowest drug concentration were reported as below the lower limit of quantitation in most laboratories. Coefficients of variation for within-laboratory values ranged from 1.1% to 10.9% for vancomycin, 0.8% to 18.2% for amikacin, 1.2% to 7.8% for gentamicin, and 1.3% to 6.1% for tobramycin. Based on the overall results of the participants, only one institution’s vancomycin samples standard deviation index exceeded 3, with all other values below 2. The College of American Pathologist criteria were met by all institutions; however, measurement of vancomycin in one laboratory and of gentamycin in three laboratories failed to meet the Royal College of Pathologists of Australasia acceptance criteria. @*Conclusions@#Although the precision of the antibiotic test in individual institutions was excellent, there was a difference in the measured values between laboratories. Harmonization of antibiotic TDM is needed to reduce inconsistencies in results.