Type of test Blood
Normal findings
Angiotensin I: ≤ 25 pg/mL
Angiotensin II: 10-60 pg/mL
Test explanation and related physiology
Renin is an enzyme that is released by the juxtaglomerular apparatus of the kidneys. Its release is stimulated by hypokalemia, hyponatremia, decreased renal blood perfusion, or hypovolemia. Renin stimulates the release of angiotensinogen. Angiotensin-converting enzyme (ACE) metabolizes angiotensinogen to angiotensin I and subsequently to angiotensin II and III. Angiotensin then stimulates the release of catecholamines, antidiuretic hormone, ACTH, oxytocin, and aldosterone. Angiotensin is also a vasoconstrictor. Angiotensin is used to identify renovascular sources of hypertension. It can be measured as angiotensin I or as angiotensin II.
Procedure and patient care
• See inside front cover for Routine Blood Testing.
• Fasting: no
• Blood tube commonly used: lavender
* Instruct the patient to maintain a normal diet with a restricted amount of sodium (∼ 3 g/day) for 3 days before the test.
* Instruct the patient to check with a healthcare provider about discontinuing any medications that may interrupt renin activity.
• Record the patient’s position, dietary status, and time of day on the laboratory slip.
• Place the tube of blood on ice and immediately send it to the laboratory.
Abnormal findings
Increased levels
- Essential hypertension
- Malignant hypertension
- Renovascular hypertension
Decreased levels
- Primary hyperaldosteronism
- Steroid therapy
- Congenital adrenal hyperplasia
