Renin, a proteolytic enzyme, is synthesized by the juxtaglomerular cells of the kidney and released in response to decreased blood volume, decreased blood pressure and sodium depletion. Renin stimulates aldosterone release through angiotensin intermediates, resulting in the renal retention of sodium and the excretion of potassium.
Renin is measured with paired aldosterone to calculate an aldosterone/renin ratio in the investigation of hypertension.
Renin measurement may be useful in monitoring response to therapy in patients with Addison's disease or congenital adrenal hyperplasia (CAH).
Beta blockers, diuretics, ACE inhibitors, angiotensin II receptor blockers, calcium channel blockers, a restricted salt diet and posture can all affect interpretation of renin results.
Sample Requirements and Reference Ranges
|Container||EDTA (Lithium heparin unsuitable)|
|Precautions||Do not collect on ice. Separate and freeze plasma. Transport frozen. Grossly haemolysed or lipaemic samples unsuitable. Posture and relevant drug therapies (see above) may affect interpretation of results.|
|Minimum volume||5 mL|
Adults (upright): <52 mIU/L
Infants <1 year: <450 mIU/L
Children 1 - 5 years: <380 mIU/L
Children 6 - 15 years: <125 mIU/L
|Turnaround time||14 days|