Renin
Code:9042
| Includes | Renin |
|---|
Analysis details
Methodology
- Enzyme immunoassay (EIA)
Expected Turnaround Time
1 day
Special Instructions
- Avoid alcohol for 24 hours before collection.
- Fast for 12 hours; water is permitted.
- With clinician approval, discontinue renin inhibitors 7 days before testing.
- With clinician approval, avoid the following agents for 24 hours before testing: captopril, chlorpropamide, diazoxide, enalapril, guanethidine, hydralazine, lisinopril, minoxidil, nifedipine, nitroprusside, potassium-sparing diuretics (amiloride, spironolactone, triamterene), and thiazide diuretics (bendroflumethiazide, chlorthalidone).
- If clinically feasible and with clinician approval, avoid all medications for 24 hours prior to collection.
- Avoid physical and emotional stress for 24 hours before collection.
- Remain in a standing or supine position for 60 minutes before phlebotomy.
- Do not smoke for 3 hours before collection.
- Collect between 07:00 and 10:00.
How to use
The Renin test, also known as direct renin or plasma renin concentration, is used to assess dysregulation of the renin–aldosterone system in the evaluation of hypertension and electrolyte abnormalities. Results are interpreted with a paired aldosterone measurement to screen for primary aldosteronism and to help distinguish primary from secondary hyperaldosteronism. It may also aid the assessment of suspected renovascular hypertension and other conditions characterized by altered renin secretion.
Limitations
Renin release from the kidney increases with reduced arterial pressure, decreased sodium concentration, or increased potassium concentration. Renin cleaves angiotensinogen to angiotensin I, which angiotensin-converting enzyme converts to angiotensin II; angiotensin II causes marked vasoconstriction and stimulates aldosterone secretion. These actions raise blood pressure and help regulate sodium and potassium homeostasis. Because of this tight physiologic linkage, renin (including direct renin concentration) is commonly measured alongside aldosterone.
| Reference interval |
| ||||
|---|---|---|---|---|---|
| Indications | Hypertension accompanied by hypokalemia, Resistant hypertension or hypertension with early onset, Suspected primary aldosteronism; order with aldosterone for interpretation |
Possible Causes of Abnormal Results
Increased levels
- morning collection
- upright posture
Specimen Requirements
| Specimen | Whole blood |
|---|---|
| Container | Lavender Top (K3 EDTA) |
| Storage Instructions | Refrigerated, Frozen |