Inclusion Criteria:  Receiving cefuroxime therapy intravenous (iv) as part of standard care Age ≥ 18 years Admitted to a general ward of Noordwest Ziekenhuisgroep - location Alkmaar Informed consent is obtained  Exclusion Criteria:  Mentally incapacitated patients, i.e. a minor or legally incompetent adult Renal replacement therapy during treatment with cefuroxime Patients admitted to the intensive care unit (ICU) Severely burned patients, defined as a burned surface ≥ 10% Patients with cystic fibrosis Informed consent is not obtained