Renin Activity
| Category | Biochemistry >> Aldosterone and Renin |
|---|---|
| Test background |
Renin is an aspartyl protease enzyme secreted by the juxto-glomerular cells located in the afferent arterioles of the kidney. It is important in control of production of angiotensin II, a vasoactive peptide that is the principal regulator, along with potassium, of aldosterone release from the adrenal glands. Renin activity is the predominant regulator of aldosterone synthesis and secretion |
| Clinical Indications |
Diagnosis of and differentiation between primary and secondary hyper- and hypo-aldosteronism Monitoring mineralocorticoid replacement therapy Management of renal artery stenosis (RAS) Diagnosis and location of renin-secreting tumours |
| Reference range | Less than six years = appropriate range will be given with the test results |
| Sample & container required | EDTA plasma preferred, heparin plasma also accepted; Samples should ideally be separated and frozen within 60 mins but must be separated within 4 hours. |
| Sample collection | Do not collect on ice or separate in a chilled centrifuge. |
| Transport storage | Store frozen and send frozen |
| Turnaround time | 4 weeks |
| Notes | The aldosterone renin ratio is used in the clinical context to support/exclude diagnosis of primary hyperaldosteronism. For primary hyperaldosteronism, correct severe hypokalaemia (plasma potassium should be ≥ 3.0 mmol/L). Patients must be receiving an adequate intake of both sodium (100-150 mmol/24 h) and potassium (50-100 mmol/24 h) and discontinue the supplementation temporarily for 24 hours before blood samples are taken. All interfering drugs should be discontinued if at all possible for a minimum of 2 weeks (aldosterone antagonists for 6 weeks). If not possible, antihypertensive drugs may be continued for an initial screening sample with the exception of spironolactone and oestrogen (stop for at least 4 weeks), β-blockers and NSAIDs (stop for at least 1 week). |