Can You Have Primary Aldosteronism With Normal Potassium?

Yes, absolutely. Having a normal potassium level does not rule out primary aldosteronism (PA) ^[1]. In fact, the vast majority of people with this condition have completely normal potassium levels ^[2].

Medical research shows that up to 90% of patients with primary aldosteronism have normal potassium levels (normokalemia, meaning the amount of potassium in your blood is within the standard healthy range) ^[1][2]. Relying on low potassium as the main warning sign is an outdated practice that prevents many patients from getting the screening they need ^[1].

The “Low Potassium” Myth

Historically, primary aldosteronism was thought to be a rare condition that mainly caused severe high blood pressure and dangerous drops in potassium ^[3]. We now know this is a misconception ^[4].

While the excess aldosterone (a hormone produced by the adrenal glands that regulates salt and water balance) produced in PA can cause your kidneys to excrete too much potassium, this is not a strict rule ^[5][6]. Serum potassium can remain normal despite extra potassium being lost in the urine, and this depends on factors like sodium intake, kidney function, and medications ^[5]. For most patients, potassium levels stay in the normal range, even while the excess aldosterone increases blood pressure and can increase the risk of cardiovascular and kidney issues if untreated ^[7][8]. Therefore, a normal potassium test does not mean your aldosterone levels are normal ^[7].

A Better Indicator: Resistant Hypertension

If normal potassium doesn’t rule out primary aldosteronism, what should prompt a doctor to test for it? A much more common everyday indicator is resistant hypertension. This is generally defined as high blood pressure that remains above target levels despite taking three blood pressure medications of different classes (usually including a diuretic, or “water pill”) at maximally tolerated doses, or blood pressure that requires four or more medications to control ^[9].

Studies show that 20-30% of people with resistant hypertension actually have primary aldosteronism ^[10]. Major endocrine and hypertension guidelines state that anyone with resistant hypertension should be screened for PA, regardless of their serum potassium levels ^[11][9].

According to major guidelines (such as those from the Endocrine Society), you should also be screened if you have:

• Sustained blood pressure at or above 150/100 mmHg ^[12]
• High blood pressure along with sleep apnea, an adrenal nodule, or a family history of early stroke or early-onset hypertension (before age 40) ^[12]
• A first-degree relative with primary aldosteronism ^[12]

Note on broader screening: More recent updates, such as the 2025 Endocrine Society guidelines, now suggest considering screening for primary aldosteronism in people with hypertension more broadly, not just those in high-risk groups ^[13].

(Note on low potassium: While low potassium isn’t required for a diagnosis, if you DO have unexplained, severely low potassium along with high blood pressure, it is a strong reason for prompt evaluation. One specialized study found that up to 88.5% of patients with spontaneous, severely low potassium (below 2.5 mmol/L) and high blood pressure had PA ^[14]. Severe hypokalemia can cause weakness and abnormal heart rhythms, so seek prompt medical care if you experience this.)

Getting the Right Test: The ARR

If you suspect you might have primary aldosteronism, your doctor should order an aldosterone-to-renin ratio (ARR) blood test ^[15][2]. This is an initial screening test that compares your aldosterone levels to renin (an enzyme produced by the kidneys that normally regulates aldosterone) ^[15].

Important Medication Warning: Do NOT stop or change your blood pressure medications on your own before this test. Several common blood pressure drugs can alter renin or aldosterone levels, which affects the ARR ^[2]. However, abruptly stopping medications can cause dangerous spikes in blood pressure. Your clinician will create an individualized, supervised plan, which may involve temporarily switching to different medications (medication washout) or interpreting the test while you remain on your current drugs ^[2].

Potassium and the ARR: While normal potassium is not an absolute requirement to draw your blood, having low potassium can temporarily suppress your aldosterone production, leading to a false-negative screening result ^[15]. For this reason, clinicians generally prefer to correct low potassium before testing, and a test done while your potassium is low may need to be repeated after it is corrected ^[2].

Remember that a positive ARR is a screening result, not a final diagnosis. If your ARR is elevated, your clinician will review the specific aldosterone and renin values, consider your medications and potassium levels, and likely recommend confirmatory testing to establish a definitive diagnosis ^[15][16].