Hypertension triple test generally includes blood renin, angiotensin, aldosterone test. Will be affected by drugs, diet, position, time and so on, check hypertension three need to pay attention to the test before stop taking antihypertensive and some other drugs, usually in the early morning, lying down, standing position, respectively, blood collection. 1. Stop taking drugs before the test: Because some drugs, such as metoprolol, sodium nitroprusside, etc., will affect the results of renin in the three hypertension tests, it is necessary to stop taking drugs for 2 weeks before the test, if the patient is not suitable to stop taking drugs, he can change to take antihypertensive drugs that have less effect on renin. 2. Prone position blood collection: stay in bed overnight or keep prone position for about 2-4 hours before blood collection, and then collect blood from vein. 3. Vertical blood sampling: it is necessary to keep the patient in the vertical position and collect blood from the vein after 2-4 hours of activity.