A client has a prescription for vital sign measurement every four hours. The nurse observes that the client's blood pressure has increased from 140/60 mm Hg at noon to 180/90 mm Hg four hours later. Which action should the nurse implement?

A. Obtain an automatic blood pressure machine for hourly readings: Increasing the frequency of monitoring may become necessary if hypertension persists, but the priority is first to verify the accuracy of the abnormal reading. A single elevated blood pressure measurement could be due to factors such as movement, improper cuff size, or positioning. B. Plan to measure the blood pressure in four hours as prescribed: Waiting another four hours could delay recognition and treatment of significant hypertension. A rise from 140/60 mm Hg to 180/90 mm Hg represents a substantial change that requires prompt reassessment rather than routine continuation of the original monitoring interval. C. Repeat the client's blood pressure measurement in fifteen minutes: When an unexpected or significantly elevated blood pressure reading occurs, the nurse should repeat the measurement after a short interval to confirm the accuracy of the finding. This reassessment helps rule out measurement error and allows the nurse to determine whether the elevation is persistent and requires further intervention or provider notification. D. Reassess the blood pressure if the client reports other symptoms: Hypertension can be asymptomatic, and waiting for symptoms such as headache, chest pain, or visual changes could delay recognition of a potentially serious condition. Clinical decisions should not rely solely on symptom reporting when objective data already show a concerning change in vital signs.