angiotensin-1/renin activity in plasma

Indications: 1) the captopril test uses plasma renin levels before & after administration of captopril 2) differentiation of primary & secondary hyperaldosteronism 3) assessment of renovascular hypertension Reference interval: 1) adults [1] a) normal diet 1] supine: 0.3-1.9 ng/mL/hour 2] upright: 0.2-3.6 ng/mL/hour b) low sodium diet: 1] supine: 0.9-4.5 ng/mL/hour 2] upright: 4.1-9.1 ng/mL/hour c) diuretics & low sodium diet: -> 6.3-13.5 ng/mL/hour 2) infants [2] a) 0-1 weeks: < 40 ng/mL/hour b) 2-4 weeks: < 175 ng/mL/hour 3) 18-39 years of age a) Na⁺-depleted: 10.8 (2.9-24.0) ng/mL/hour b) Na⁺-repleted: 1.0 (<0.6-4.3) ng/mL/hour 4) > 39 years of age a) Na⁺-depleted: 5.9 (2.0-10.8) ng/mL/hour b) Na⁺-repleted: 1.0 (<0.6-3.0) ng/mL/hour Increases: 1) pharmaceutical_agents -> in vivo effects -> ACE inhibitors, chlorpropamide, diazoxide, estrogens, guanethidine (with Na⁺ depletion), hydralazine, minoxidil, nifedipine, nitroprusside, K⁺ sparing diuretics, thiazides 2) clinical disorders a) with secondary hyperaldosteronism 1] hypertensive states a] severe or malignant hypertension with or without unilateral kidney disease b] renal parenchymal disease c] renin-secreting tumors d] oral contraceptive-induced hypertension e] pheochromocytoma 2] edematous non-hypertensive states a] cirrhosis b] hepatitis c] nephrosis d] congestive heart failure 3] hypokalemic normotensive states a] juxtaglomerular cell hyperplasia (Bartter's syndrome) b] nephropathies with Na⁺ or K⁺ wastage c] gastrointestinal disorders with electrolyte loss b) without secondary hyperaldosteronism 1] adrenocortical insufficiency 2] K⁺ depletion state (gastrointestinal) 3] pregnancy 3) cyroactivation of prerenin (chilled tubes) Decreases: 1) pharmaceutical_agents -> in vivo effects -> beta blockers, angiotensin (IV), aspirin, carbenoxolone, clonidine, deoxycorticosterone, guanethidine (normal Na⁺), indomethacin, licorice, methyldopa, K⁺, prazosin, reserpine 2) clinical disorders a) with adrenocortical disease -> hypertensive states a] primary hyperaldosteronism due to adrenal adenoma b] bilateral adrenocortical hyperplasia c] glucocorticoid-suppressible hyperaldosteronism d] adrenal carcinoma with mineralocorticoid excess e] adrenal enzymatic defects resulting in excess secretion of mineralocorticoids b) without adrenocortical disease 1] hypertensive states a] low-renin essential hypertension b] renal parenchymal disease c] Liddle's syndrome 2] normotensive states a] renal parenchymal disease b] autonomic disorders with postural hypotension c] uninephrectomized subjects d] hyperkalemia Method: 1) RIA for angiotensin-1 2) plasma renin activity is measured indirectly by the ability of the patient's plasma to generate angiotensin-1* 3) simultaneous measurement of 24 hour urine Na⁺ & creatinine & serum/plasma Na⁺, K⁺ & creatinine are recommended angiotensinogen ----- renin ------> angiotensin-1 Specimen: 1) plasma (Na2EDTA, Lavender top) 2) place in ice water & centrifuge at 4 degrees C 3) separate plasma at freeze promptly at -20 degrees C 4) stable for up to 1 year

General

analyte ratio

References

Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
ABC's of Interptretive Laboratory Data, 4th ed, Bakerman S et al (eds), Interpretive Laboratory Data Inc, Scottsdale, AZ, 2003 http://www.bakermanbooks.com
Panel of 3 tests Laboratory Test Directory ARUP: 70073
Renin Activity Laboratory Test Directory ARUP: 70105
Direct Renin Laboratory Test Directory ARUP: 2001575
Panel of 3 tests Laboratory Test Directory ARUP: 2002582

Component-of

hypertension panel

Components

angiotensin 1 in plasma renin in plasma

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