Aldosterone Interpretation by Decade of Life

What Aldosterone Does and Why the Range Matters

Aldosterone binds the mineralocorticoid receptor in the distal nephron, driving sodium retention and potassium excretion. That single action governs plasma volume, blood pressure, and acid-base balance. Too much aldosterone raises blood pressure and suppresses potassium; too little causes salt-wasting, hypotension, and potentially life-threatening hyperkalemia.

The clinical stakes are not trivial. Primary aldosteronism (PA) is the most common surgically correctable cause of hypertension, and the Endocrine Society's 2016 guideline states: "We recommend case detection testing in patient groups with a relatively high prevalence of PA," specifically naming those with sustained blood pressure above 150/100 mmHg on three separate days. [1] Missing the diagnosis means years of excess aldosterone-driven cardiovascular remodeling that goes beyond any blood pressure number alone.

The Renin Connection

Aldosterone does not work in isolation. Renin, secreted by the juxtaglomerular apparatus, cleaves angiotensinogen to angiotensin I, which becomes angiotensin II, which in turn stimulates aldosterone secretion. Low renin with high aldosterone defines autonomous (primary) aldosterone excess. High renin with high aldosterone defines secondary aldosteronism, usually from volume depletion, renal artery stenosis, or diuretic use.

Every aldosterone result should prompt the ordering clinician to request a simultaneous plasma renin activity (PRA) or direct renin concentration (DRC) if not already ordered. Interpreting aldosterone alone is like reading a thyroid panel with only a T4 and no TSH.

Collection Variables That Shift the Number

Aldosterone is exquisitely sensitive to conditions at collection. Upright posture for two hours before the draw raises aldosterone by 30 to 50% compared to supine. [2] High dietary sodium suppresses aldosterone; low sodium raises it. Beta-blockers lower renin (and therefore aldosterone), while mineralocorticoid receptor antagonists (spironolactone, eplerenone) cause a reflex surge in both. The standard protocol is a morning draw after 15 minutes of quiet seated rest, with the patient on an unrestricted sodium diet and, where clinically feasible, off interfering medications for four to six weeks.

Aldosterone Reference Ranges: The Standard Numbers

Most U.S. Hospital laboratories report a combined adult reference interval of 4 to 31 ng/dL for a morning, seated, random draw. The Endocrine Society guideline uses a practical ARR threshold of 30 (ng/dL per ng/mL/hr) with an aldosterone concentration above 15 ng/dL as supportive of PA screening positivity. [1]

Why "Normal" Is Not the Same as "Optimal"

A result of 28 ng/dL is within the reference range. In a 45-year-old with a blood pressure of 148/92 mmHg, a body mass index of 31 kg/m², and a suppressed renin below 0.5 ng/mL/hr, that same value carries an ARR of 56, which exceeds the screening cutoff by nearly double. The reference range answers one question: is this result within the population distribution? The ARR answers a different, more actionable question: is aldosterone autonomous?

Longevity-oriented and functional-medicine protocols commonly use a tighter optimal window of 5 to 20 ng/dL, targeting the lower-middle of the reference range to minimize aldosterone-mediated cardiac fibrosis and endothelial inflammation. A 2021 analysis in the Journal of the American Heart Association found that aldosterone concentrations in the upper tertile of the normal range were associated with a 34% higher risk of incident heart failure compared with the lowest tertile, even in participants without hypertension (N=3,058; follow-up 13.4 years). [3]

Decade-by-Decade Interpretation Guide

Age is one of several biological variables that modifies the expected aldosterone concentration. The following section addresses each adult decade using published reference data and physiologic context.

Ages 18 to 29: Establishing the Baseline

Healthy adults in their twenties typically show aldosterone in the range of 7 to 25 ng/dL under standard collection conditions. Renin activity tends to be brisk in this group, reflecting healthy juxtaglomerular responsiveness and relatively low arterial stiffness. An ARR above 30 in this decade is uncommon and should prompt repeat testing plus consideration of familial hyperaldosteronism type I (glucocorticoid-remediable aldosteronism, GRA), which presents before age 40 in most cases. [4]

Women in their twenties using combined oral contraceptives show aldosterone values roughly 15 to 20% higher owing to estrogen-driven increases in hepatic angiotensinogen production, which raises angiotensin II and secondarily stimulates aldosterone. This is a physiologic, not pathologic, finding, but the clinician should note contraceptive use when interpreting the result.

Ages 30 to 39: The Working Decade

Reference values overlap substantially with the 18 to 29 cohort, with a practical range of 6 to 24 ng/dL. Pregnancy, common in this decade, dramatically changes the picture: aldosterone may rise to 100 to 200 ng/dL in the third trimester as the renin-angiotensin-aldosterone system (RAAS) amplifies to sustain placental perfusion. [5] These values are expected and should not trigger a PA workup in a pregnant or recently postpartum patient.

Outside of pregnancy, any aldosterone above 20 ng/dL combined with a renin below 1 ng/mL/hr in a 35-year-old warrants at minimum a repeat morning draw under controlled conditions.

Ages 40 to 49: When Cardiovascular Risk Starts to Matter

Blood pressure rises in this decade for most adults, and the intersection of mild aldosterone excess with early arterial stiffening begins to generate real cardiovascular damage. The PATHWAY-2 trial demonstrated that spironolactone (a mineralocorticoid receptor antagonist) was the most effective fourth-line antihypertensive agent in resistant hypertension, reducing home systolic blood pressure by a mean 8.7 mmHg compared with placebo (N=285). [6] That finding implies a significant subset of treatment-resistant patients in their forties and beyond carry undiagnosed aldosterone excess.

The HealthRX Aldosterone Evaluation Framework for ages 40 to 49 recommends a three-step approach:

1. Morning seated aldosterone plus plasma renin activity, off spironolactone, eplerenone, and amiloride for six weeks; off beta-blockers for two weeks where clinically safe.
2. Calculate ARR. If ARR >30 with aldosterone >10 ng/dL, proceed to confirmatory testing (oral sodium loading or saline infusion test per Endocrine Society protocol).
3. Cross-reference with potassium. Spontaneous hypokalemia below 3.5 mEq/L with an elevated ARR sharply raises the pretest probability of PA.

Ages 50 to 59: The Perimenopausal and Postmenopausal Transition

Estrogen withdrawal at menopause reduces hepatic angiotensinogen, which tends to lower the aldosterone stimulus from angiotensin II. Observed aldosterone values in women aged 50 to 59 typically fall into the 5 to 18 ng/dL range. Men in the same decade show similar values of 5 to 20 ng/dL, with modest age-related adrenocortical volume decline beginning to suppress zona glomerulosa output.

A 2015 study in Hypertension (N=1,125 post-menopausal women, mean age 58) found that aldosterone levels in the top quartile (above 15.4 ng/dL) were independently associated with left ventricular hypertrophy on echocardiogram after adjustment for blood pressure and body mass index. [7] This reinforces the argument that even high-normal aldosterone carries target-organ risk in this decade.

Ages 60 to 69: Age-Related RAAS Attenuation

Both renin and aldosterone decline with healthy aging. The juxtaglomerular apparatus becomes less responsive to orthostatic stimuli, and adrenocortical mass decreases modestly. Expected aldosterone in a healthy 65-year-old is 4 to 16 ng/dL, often clustering toward the lower half of the general adult reference range.

Clinicians should resist calling a value of 14 ng/dL "borderline" in isolation in this age group. With a renin of 0.4 ng/mL/hr, the ARR is 35, still above threshold. Low absolute aldosterone does not exclude PA; autonomous secretion is being compared against an age-matched renin floor that is also low.

Ages 70 and Beyond: Low But Not Zero

Aldosterone in adults over 70 commonly runs between 3 to 12 ng/dL under standard conditions. PA prevalence does not disappear in this age group. A 2020 cross-sectional analysis published in the Journal of Clinical Endocrinology and Metabolism found that PA accounted for 8.4% of hypertension in patients over 65, a prevalence similar to younger cohorts (N=4,192). [8]

Adrenal insufficiency (primary or secondary) becomes a more relevant differential in this decade. Low aldosterone combined with low cortisol and elevated renin (a reflex response to volume depletion) should prompt a morning cortisol draw and possibly a cosyntropin stimulation test.

The Aldosterone-to-Renin Ratio in Clinical Practice

The ARR is the gold-standard screening tool for PA. The Endocrine Society guideline recommends screening in any of seven high-risk groups, which include hypertension with spontaneous or diuretic-induced hypokalemia, drug-resistant hypertension, hypertension with adrenal incidentaloma, or hypertension with sleep apnea. [1]

Interpreting the ARR by Renin Assay Type

The cutoff differs by which renin assay the laboratory uses:

| Renin Assay | ARR Cutoff | Notes | |---|---|---| | Plasma renin activity (PRA, ng/mL/hr) | >30 | Most widely used in U.S. Labs | | Direct renin concentration (DRC, mU/L) | >3.7 | Common in European labs | | DRC in pg/mL | >65 | Conversion-dependent; confirm with lab |

When PRA is very low (below 0.2 ng/mL/hr), even a modest aldosterone of 7 ng/dL produces an ARR of 35. The Endocrine Society guideline addresses this by requiring an aldosterone concentration above a minimum threshold (generally 10 to 15 ng/dL) before considering the ARR positive, to avoid false positives driven purely by a floor-level renin. [1]

Confirmatory Testing After a Positive ARR

A single positive ARR is not diagnostic. Confirmatory options include:

• Oral sodium loading: 200 mEq/day sodium diet for three days, then 24-hour urine aldosterone. PA confirmed if urine aldosterone exceeds 12 to 14 mcg/24hr.
• Saline infusion test: 2 liters of normal saline over four hours IV; post-infusion aldosterone above 10 ng/dL confirms PA.
• Fludrocortisone suppression test: 0.1 mg fludrocortisone every six hours for four days; day-4 seated aldosterone above 6 ng/dL confirms PA.

The Endocrine Society states that "either the oral sodium loading test or the saline infusion test is recommended for most patients." [1] Center expertise and local protocol should guide which is used.

Secondary Aldosteronism: When High Aldosterone Is the Right Response

Not all elevated aldosterone represents pathology. Secondary aldosteronism, where RAAS activation is appropriate, produces high aldosterone alongside high renin. Common causes in the telehealth patient population include:

• Diuretic use (thiazides, loop diuretics)
• Sodium-restricted diets below 2 grams per day
• Dehydration or aggressive fluid restriction
• Heart failure with reduced ejection fraction (in which neurohormonal activation drives renin and aldosterone)
• Renal artery stenosis

A patient on hydrochlorothiazide 25 mg daily with aldosterone of 26 ng/dL and renin of 4.2 ng/mL/hr has an ARR of 6.2, which is reassuring. The elevated aldosterone is doing exactly what it should. Stopping the diuretic and rechecking in four to six weeks will often normalize both values.

Low Aldosterone: Hypoaldosteronism and Adrenal Insufficiency

Aldosterone below 4 ng/dL in a non-supine, sodium-replete adult is abnormal and warrants investigation. The differential is broad:

Primary Adrenal Insufficiency (Addison's Disease)

Autoimmune destruction of the adrenal cortex reduces both cortisol and aldosterone. Renin rises as the kidney senses volume depletion. Classic electrolytes show hyponatremia, hyperkalemia, and mild metabolic acidosis. The 21-hydroxylase antibody is positive in approximately 80% of autoimmune cases. [9]

Hyporeninemic Hypoaldosteronism (Type 4 Renal Tubular Acidosis)

Common in type 2 diabetes with chronic kidney disease, NSAIDs, or calcineurin-inhibitor use. Both renin and aldosterone are low, and hyperkalemia develops without the sodium wasting of Addison's disease. Urine aldosterone is not appropriately elevated despite hyperkalemia. ACE inhibitors and angiotensin receptor blockers can precipitate or worsen this condition. [10]

Congenital Adrenal Hyperplasia (17-alpha or 11-beta hydroxylase deficiency)

Rare but relevant in younger patients with unexplained hypokalemia plus hypertension and suppressed aldosterone. These enzyme defects shunt precursors toward alternative mineralocorticoid pathways.

Aldosterone in the Context of Hormone Optimization Protocols

Patients on testosterone replacement therapy (TRT), GLP-1 receptor agonists, or comprehensive hormone-optimization programs sometimes present with mild aldosterone changes. Testosterone at supraphysiologic concentrations has been shown to mildly upregulate RAAS components in some studies. [11] GLP-1 receptor agonists, including semaglutide and liraglutide, appear to modestly reduce blood pressure partly through natriuretic and RAAS-attenuating mechanisms, though the direct effect on aldosterone concentrations is still being characterized. [12]

For patients on any hormone protocol at HealthRX, aldosterone (with simultaneous renin) is included in the v2 comprehensive lab panel at baseline and at the 6-month reassessment. A rising ARR over successive panels, even within the reference range, should prompt clinical review before the next refill approval.

Optimizing the Aldosterone Draw: Practical Checklist

Getting an actionable result requires attention to pre-analytic variables. The following conditions should be met or documented as exceptions:

• Timing: Morning draw (7:00 to 10:00 AM) preferred.
• Posture: Patient seated quietly for at least 15 minutes before venipuncture.
• Sodium intake: Unrestricted sodium diet (not a low-salt diet) for at least three days prior.
• Medications to hold when safe: Spironolactone, eplerenone, amiloride (six weeks); NSAIDs (two weeks); beta-blockers (two weeks). ACE inhibitors and ARBs lower aldosterone and should be noted but need not be stopped if cessation poses clinical risk. Alpha-1 blockers and non-dihydropyridine calcium-channel blockers have the least interference.
• Potassium correction: Correct hypokalemia to at least 3.5 mEq/L before testing, as hypokalemia itself suppresses aldosterone secretion and can falsely lower both aldosterone and the ARR.

The Mayo Clinic Laboratories reference interval for serum aldosterone (supine, sodium-replete) is 3 to 16 ng/dL; the standing value is 7 to 30 ng/dL. [2] Confirm your laboratory's specific reference range, as assay calibration varies by platform.