A nurse is reviewing the diagnostic test results of an older adult female client who is preoperative for a knee arthroplasty. The nurse should notify the surgeon of which of the following results?

Choice A reason: A hematocrit level of 40% is within the normal range for adult females, typically between 36% and 46%. This value does not indicate anemia or polycythemia and would not warrant notifying the surgeon prior to surgery. Choice B reason: A creatinine level of 0.9 mg/dL is considered normal for adult females, generally ranging from 0.6 to 1.1 mg/dL. This value suggests adequate renal function and does not pose a contraindication for surgery. Choice C reason: A white blood cell (WBC) count of 20,000/mm³ is significantly elevated above the normal range of 4,000 to 11,000/mm³. This may indicate an active infection, inflammation, or hematologic disorder. Surgery should be postponed until the cause is identified and treated, as proceeding with surgery in the presence of infection increases the risk of postoperative complications. Choice D reason: A potassium level of 3.3 mEq/L is slightly below the normal range of 3.5 to 5.0 mEq/L. While mild hypokalemia should be corrected, it is not as urgent as a markedly elevated WBC count, which could indicate a systemic infection requiring immediate attention.