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Sodium Test

Sodium Test

January 21, 2026
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Do I need a Sodium test?

Feeling unusually tired, confused, or experiencing muscle cramps or weakness? Could your sodium levels be off balance, and might a simple test reveal what's going on?

Sodium is essential for nerve function, muscle contraction, and fluid balance throughout your body. When levels drift too high or low, you may experience fatigue, confusion, cramping, or weakness.

Testing your sodium gives you a quick snapshot of your electrolyte balance, helping pinpoint whether imbalances are contributing to your symptoms. It's the first step toward personalizing your hydration strategy, dietary choices, and overall wellness plan so you can feel stronger and more balanced.

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Get tested with Superpower

If you’ve been postponing blood testing for years or feel frustrated by doctor appointments and limited lab panels, you are not alone. Standard healthcare is often reactive, focusing on testing only after symptoms appear or leaving patients in the dark.

Superpower flips that approach. We give you full insight into your body with over 100 biomarkers, personalized action plans, long-term tracking, and answers to your questions, so you can stay ahead of any health issues.

With physician-reviewed results, CLIA-certified labs, and the option for at-home blood draws, Superpower is designed for people who want clarity, convenience, and real accountability - all in one place.

Key benefits of Sodium testing

  • Confirms your body's fluid and electrolyte balance are in healthy range.
  • Spots dehydration or overhydration that may explain fatigue or confusion.
  • Flags kidney or hormone disorders affecting sodium regulation early.
  • Guides treatment if you're on diuretics, heart medications, or IV fluids.
  • Clarifies causes of muscle cramps, weakness, or unexplained nausea.
  • Tracks sodium trends during illness, surgery recovery, or chronic disease management.
  • Best interpreted with potassium, kidney function tests, and your symptoms.

What is Sodium?

Sodium is a mineral and electrolyte that circulates in your blood and bathes every cell in your body. It enters your system primarily through the salt (sodium chloride) you eat and drink, and your kidneys tightly regulate how much stays in or leaves through urine.

Your body's master volume control

Sodium acts like a magnet for water. Where sodium goes, water follows. This property makes it the main driver of fluid balance, controlling blood volume, blood pressure, and the amount of water inside and outside your cells.

The spark behind every nerve signal and muscle contraction

Sodium also carries an electrical charge that powers cellular communication. It flows rapidly across cell membranes to generate the electrical impulses that let nerves fire, muscles contract, and your heart beat in rhythm. Without precisely balanced sodium, these vital signals falter.

When you measure sodium in blood, you're checking whether your body is maintaining the delicate equilibrium between water, salt, and cellular function.

Why is Sodium important?

Sodium is the body's master regulator of fluid balance, blood pressure, and electrical signaling across every cell. It governs how water moves between blood vessels, tissues, and cells, and it enables nerves to fire and muscles to contract. Normal blood sodium sits in a narrow range, typically 135–145, and the body defends this tightly because even small shifts disrupt brain function, heart rhythm, and organ perfusion.

Your brain notices sodium shifts first

When sodium drops below normal, water floods into cells, causing brain swelling. This triggers confusion, headache, nausea, and in severe cases, seizures or coma. Muscles weaken, blood pressure falls, and fatigue becomes profound as cells lose their electrical charge.

High sodium pulls water where it shouldn't go

Elevated sodium draws water out of cells and into the bloodstream, shrinking brain tissue and triggering intense thirst, irritability, and restlessness. Blood pressure climbs as vessels overfill. Severe cases cause muscle twitching, altered consciousness, and dangerous heart arrhythmias.

Sodium connects fluid, pressure, and every organ system

Because sodium dictates where water flows, it directly influences kidney function, heart workload, and hormonal systems like aldosterone and antidiuretic hormone. Chronic imbalances strain the cardiovascular system, accelerate kidney disease, and increase stroke risk. Sodium is not just an electrolyte - it's the pivot point for whole-body hydration and cellular communication.

What do my Sodium results mean?

Low sodium usually reflects dilution or loss

Low values usually reflect either excess water retention that dilutes the blood or true sodium loss through the kidneys, gut, or skin. The body tightly regulates sodium to maintain fluid balance and nerve and muscle function. When sodium drops, cells can swell, especially in the brain, leading to confusion, fatigue, nausea, or headache. Common causes include certain diuretics, heart failure, liver disease, kidney dysfunction, or conditions that impair water excretion like low thyroid hormone or adrenal insufficiency. Severe or rapid drops can be dangerous.

Optimal sodium reflects stable fluid and electrolyte balance

Being in range suggests your kidneys, adrenal glands, and fluid regulation systems are working well together. Sodium sits at the center of how your body controls blood pressure, nerve signaling, and the movement of nutrients into cells. Most labs define normal as roughly 135 to 145 millimoles per liter, and optimal values typically sit in the mid-range, reflecting neither dehydration nor dilution.

High sodium usually reflects dehydration or impaired water balance

High values usually reflect water loss outpacing sodium loss, often from dehydration, fever, diarrhea, or inadequate fluid intake. Less commonly, it signals excess sodium retention due to kidney disease, certain hormonal imbalances like high aldosterone or cortisol, or diabetes insipidus where the kidneys cannot concentrate urine. Elevated sodium can cause thirst, confusion, and muscle twitching.

Context matters in sodium interpretation

Sodium levels shift with hydration status, medications, acute illness, and sample handling, so interpretation requires clinical context and sometimes repeat testing.

Method: FDA-cleared clinical laboratory assay performed in CLIA-certified, CAP-accredited laboratories. Used to aid clinician-directed evaluation and monitoring. Not a stand-alone diagnosis.

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Frequently Asked Questions

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How it works
What should I expect during a blood draw?
  • A trained phlebotomist will guide you through the process.
  • A tourniquet is placed on your arm, the site is cleaned, and a small needle is used to collect blood into one or more tubes.
  • Results are usually ready in about a week.
  • Most people feel only a quick pinch.
  • The needle is removed, gentle pressure is applied, and a bandage is placed.
How do I prepare for a blood draw?
  • Drink plenty of water beforehand — hydration makes veins easier to find.
  • Wear loose sleeves so your arm is easy to access.
  • Follow any fasting instructions you’ve been given.
  • Let us know if you’re on medications, have fainted before, or have needle anxiety.
What should I do after my blood draw?
  • Press gently on the site for a few minutes.
  • Keep the bandage on for 4-6 hours.
  • Skip heavy lifting or strenuous exercise for the rest of the day.
  • Drink extra water to rehydrate.
  • Monitor the site for redness, swelling, or pain.
How do I book a blood draw with Superpower?

Your membership includes:

  • An annual full body test and report across 100+ biomarkers
  • A personalized action plan to optimize your biomarkers and reach your health goals
  • A dashboard to centralize your health data and track changes across a lifetime
  • Access to a health concierge for questions on your plan and help scheduling
  • Plus a marketplace of curated health products and services cheaper than amazon

Many concierge clinics charge $10k – $100k for their services, we’ve built technology to make the world’s best healthcare as accessible as possible via an all-in-one membership.

Where can I take my blood test?

Superpower is currently available in the following US states:

  • Alabama
  • Arizona
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  • Colorado
  • Connecticut
  • Delaware
  • District of Columbia
  • Florida
  • Georgia
  • Idaho
  • Illinois
  • Indiana
  • Kansas
  • Maine
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  • Michigan
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  • Missouri
  • Montana
  • Nebraska
  • Nevada
  • New Hampshire
  • New Jersey
  • New Mexico
  • New York
  • North Carolina
  • Ohio
  • Oklahoma
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  • Pennsylvania
  • South Carolina
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  • Texas
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  • Virginia
  • Washington
  • West Virginia
  • Wisconsin
Our testing
Does Superpower replace my primary care provider?

Superpower specializes in prevention-based testing and treatments and is not intended for emergency or immediate health issues.

While you will have a Superpower care team, your annual membership is designed to complement a primary care doctor if you have one, not replace them.

We are happy to help you share any test results with an outside provider to ensure you receive well-rounded medical care.

How fast are blood test results and how do I read them?

Your annual lab test panel takes about a week to process. We will text you as soon as they become available in your dashboard. Other types of tests may have different testing windows. The Superpower concierge is your own health assistant who helps answer your questions on your results, ensure smooth scheduling, coordination of any office-based tests, specialist referrals as needed, and navigating you to interface with your care team.

Does Superpower accept health insurance?

Superpower membership and products are all eligible for HSA/FSA funding.

We see Superpower like a gym membership for those committed to prevention and performance. Superpower is a bridge between wellness and healthcare. Health insurance traditionally focuses on reactive care whereas, at Superpower, we believe it’s never too early to start looking out for your long-term health.

What if I want more than 1 blood test per year?

Absolutely — you're not limited to just one. Your membership includes one comprehensive 100+ biomarker blood test each year, but if you'd like to track your progress more closely, you can add extra tests at any time. Each additional full-panel test costs $179. You can order as many as you'd like throughout the year.

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Frequently Asked Questions about Sodium Test

What is sodium in the body, and why is it called the body’s most abundant electrolyte?

Sodium is a positively charged mineral (electrolyte) that circulates in your blood and surrounds your cells. It mainly comes from dietary salt (sodium chloride). Sodium is considered the body’s most abundant electrolyte because it’s the primary electrolyte in extracellular fluid, where it helps maintain fluid balance, supports nerve signaling, and enables muscle contraction. Your kidneys tightly regulate sodium to keep blood levels in a narrow range.

How does a sodium blood test measure hydration and electrolyte balance?

A sodium blood test measures the concentration of sodium in your blood, helping assess hydration status and electrolyte health. Because sodium controls water movement between blood vessels, tissues, and cells, abnormal results can indicate dehydration, overhydration, or impaired kidney and hormone regulation. Sodium testing is especially useful when symptoms like fatigue, confusion, or muscle cramps suggest electrolyte imbalance, and it’s often interpreted alongside potassium and kidney function markers.

What is the normal sodium range (135–145), and what does “optimal” sodium mean?

Most labs consider normal blood sodium to be about 135–145 mmol/L. “Optimal” typically refers to values in the mid-range, reflecting stable hydration and well-coordinated regulation between the brain, kidneys, and adrenal hormones. When sodium stays in range, it supports healthy blood pressure, normal nerve firing, and proper muscle contraction - including heart muscle function. Small shifts can still matter depending on symptoms, hydration, and medications.

What causes low sodium (hyponatremia), and is it usually too little salt or too much water?

Low sodium (hyponatremia) usually reflects too much water relative to sodium - dilution - rather than a true lack of dietary salt. Common causes include elevated antidiuretic hormone (ADH) due to stress, nausea, or illness, plus medications (notably diuretics and some antidepressants). Heart, liver, or kidney dysfunction can also contribute. True sodium depletion can occur with heavy sweating, vomiting, or diuretic use.

What symptoms can low sodium cause, and when can it become dangerous?

Low sodium can cause confusion, fatigue, headache, nausea, weakness, and muscle cramps. It becomes more dangerous when sodium drops rapidly or to very low levels, because cells - especially brain cells - can swell. Severe hyponatremia may lead to seizures or coma. Older adults and people taking multiple medications are often at higher risk. Symptoms plus sodium level trends help determine urgency and next steps.

What causes high sodium (hypernatremia), and does it always mean you ate too much salt?

High sodium (hypernatremia) most often signals dehydration - water loss exceeding sodium loss - rather than excess salt intake. Causes include inadequate fluid intake, excessive sweating, diarrhea, and high urine output (including uncontrolled diabetes). Kidney regulation problems can also contribute. While high salt intake can play a role, the common driver is insufficient body water. The brain is particularly sensitive to high sodium levels, so symptoms matter.

What are the symptoms of high sodium, and why does it affect the brain and cognition?

High sodium can cause intense thirst, dry mouth, restlessness, weakness, irritability, and confusion. It affects cognition because elevated sodium pulls water out of cells, including brain cells, which can impair normal function. Severe hypernatremia can lead to altered mental status and, in extreme cases, seizures or coma. Chronic elevation can strain the cardiovascular system, raising blood pressure and increasing long-term stroke and heart disease risk.

How do kidneys and hormones like ADH and aldosterone regulate sodium and fluid balance?

Your kidneys regulate sodium by adjusting how much is excreted or retained in urine. Hormones coordinate this process: antidiuretic hormone (ADH) controls water retention, while aldosterone promotes sodium retention (and affects fluid volume and blood pressure). Together, these systems keep sodium in a narrow range and maintain stable blood volume. Abnormal sodium results can indicate kidney issues or hormone-related fluid regulation problems (including adrenal or thyroid-related issues).

How do medications like diuretics, antidepressants, IV fluids, or other treatments change sodium results?

Diuretics can lower sodium by increasing urinary salt and water loss, while some antidepressants can contribute to dilutional hyponatremia through ADH-related effects. IV fluids can raise or dilute sodium depending on the type and volume given. Because sodium responds to treatment changes, testing helps track response to diuretics, IV fluids, and other medications that affect electrolyte balance. Interpretation should consider recent medication adjustments and current symptoms.

Why should sodium results be interpreted with potassium, kidney function tests, and your current symptoms?

Sodium balance is closely linked with potassium, kidney function, and hormone signaling that controls fluid regulation. Two people with the same sodium value can have very different causes and risks depending on hydration, medications, and symptoms like fatigue, cramps, thirst, or confusion. Kidney markers help identify impaired regulation, while potassium adds context for overall electrolyte status and muscle/heart function. Symptom-guided interpretation improves accuracy and supports better treatment decisions.

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