Before administering an antibiotic that can cause nephrotoxicity, which laboratory value is most important for the practical nurse (PN) to review?

A. Hemoglobin and Hematocrit: These values reflect red blood cell status and oxygen-carrying capacity but do not provide information about kidney function. They are not directly relevant to assessing risk for nephrotoxicity before antibiotic administration. B. Serum calcium: Calcium levels indicate electrolyte and bone metabolism status but do not assess renal function. Monitoring calcium is unrelated to the risk of nephrotoxic effects from antibiotics. C. Serum creatinine: Serum creatinine is a key indicator of kidney function and glomerular filtration. Reviewing this value helps the PN determine if the client’s kidneys can safely handle nephrotoxic antibiotics and guides dosing decisions to prevent further renal injury. D. White blood cell count (WBC): WBC indicates immune response and infection status but does not assess renal function. While important for infection monitoring, it does not inform nephrotoxicity risk.