Evaluation of serial creatinine measurements with reference change value in gentamicin-treated patients: a new tool in nephrology practice?

Introduction In this study, we aimed to evaluate serum creatinine levels with reference change value in patients receiving treatment with gentamicin. Methods Serum creatinine levels of patients who received gentamicin were recorded retrospectively before treatment and on the 7th and 14th days after treatment. Analytical coefficient of variation (s/x) x 100 (CV) and reference change value were calculated (z = 1.64,; P < .05). The percentage increase in serum creatinine level at day 7 and day 14 compared with before treatment was considered statistically significant if it exceeded the reference change value. Nephrotoxicity was assessed by comparing changes in serum creatinine levels using reference change value and Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Results A total of 55 patients with a mean (SD) age of 53 (17) years were included in the study. The reference change value for serum creatinine was calculated as11.9%. The rate of increase in serum creatinine levels showed a statistically significant increase in 45.5% and 63.6% of patients on days 7 and 14, respectively, compared with before treatment, while the increase was statistically significant in 8.2% and 25.5% of patients, respectively, when evaluated by KDIGO criteria. Discussion We believe that it would be in the patient's best interest for clinicians to include reference change value in clinical nephrology practice alongside known acute kidney failure criteria.