A nurse is caring for a client who has a new prescription for cefazolin. Which of the following findings should the nurse identify as a contraindication to the administration of cefazolin?

Administering cephalosporin antibiotics requires an assessment of immunological cross reactivity and potential organ toxicity. Knowledge of pharmacology, hypersensitivity mechanisms, and structural similarities between beta lactam antibiotic classes must be applied to identify unsafe prescriptions. Choice A rationale White blood cell count determines the presence of infection or leukopenia but does not contraindicate cefazolin. The normal range is 4500 to 11000 cells per microliter, and abnormal values require monitoring, not drug withholding. Choice B rationale Amylase levels evaluate pancreatic function, with a normal reference range of 30 to 110 units per liter. Pancreatic enzymes do not interact with cephalosporin metabolism or present a pharmacological contraindication to drug administration. Choice C rationale Elevated temperature indicates an active infectious or inflammatory process, which is the primary therapeutic indication for starting antibiotic therapy. Hyperthermia is an expected finding, not a clinical contraindication to cefazolin. Choice D rationale Furosemide can potentially increase cephalosporin nephrotoxicity when administered concurrently in high doses. However, it requires close monitoring of renal function labs rather than presenting an absolute, direct contraindication to therapy. Choice E rationale Allergy history is a critical contraindication because cefazolin is a cephalosporin with potential cross sensitivity to penicillins. Severe past hypersensitivity reactions can trigger life threatening anaphylaxis due to the shared beta lactam ring structure..