A blood pressure level of 150 mmHg is considered elevated but not diagnostic of hypertension. Hypertension can be diagnosed by a systolic blood pressure greater than or equal to 140 mmHg and/or a diastolic blood pressure greater than or equal to 90 mmHg on three occasions in a quiet state, not on the same day. A single blood pressure level above normal is not diagnostic of hypertension, but repeated monitoring of the blood pressure level is necessary to ensure the accuracy of the blood pressure measurements, and the diagnosis of hypertension can only be made if the blood pressure level exceeds the normal value on three occasions. Measurements must be taken in a quiet state to avoid interference from other factors. Smoking, drinking and eating are not allowed before measuring blood pressure, and qualified sphygmomanometers are used for the measurements. If there is an error in measuring the blood pressure level, it is necessary to try to take the average of the measurements several times. If the blood pressure level is high, it should be tested repeatedly and, if necessary, go to the hospital for diagnosis and treatment under the guidance of a physician.