Skip to content

24-Hour Sodium Urine Collection (Total Sodium Content)

Published: August 9, 2026Updated: August 16, 2026

This test measures the total amount of sodium (a key electrolyte) excreted in your urine over a 24-hour period. It helps assess how well your kidneys are regulating sodium balance, which is important for blood pressure and fluid balance.

Quick summary

["This test helps evaluate kidney function and electrolyte balance over time."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
59163-6
Short code
Sodium 24h Stl-sCnc
Synonyms
Sodium 24h Stl-sCnc
Category
electrolyte
Sample
stool
Container
Clean container
Units
N/A
Ref low
136
Ref high
145
Critical range
120 N/A – 160 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84295
SNOMED
110741000
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may recommend this test if you have symptoms like high blood pressure, swelling, frequent urination, or if you’re being treated for conditions like kidney disease, heart failure, or certain medications that affect sodium levels. It can also help monitor long-term sodium excretion in chronic conditions.

What Does the Test Involve?

You’ll collect all urine for 24 hours, typically starting after midnight on one day and ending after midnight the next. Store the urine in a refrigerator or at room temperature, and bring the entire sample to your lab. Some clinics provide special containers to make collection easier.

How Is the Test Performed?

The lab analyzes the collected urine sample to determine the total sodium content. This is done using a method like ion-selective electrode (ISE) or chemiluminescence, which measures sodium concentration in the urine.

What Do Results Mean?

Results are compared to your baseline or clinical needs rather than a fixed reference range. High sodium excretion may indicate overactive kidneys or certain medications, while low levels could suggest kidney dysfunction or fluid retention. Your doctor will interpret results in the context of your health and symptoms.

Reference range

Adult: 136-145 mmol/LN/A

Specimen: stool

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Sodium Urine Test

Frequently asked questions

What causes abnormal sodium excretion in urine?
Several factors can affect sodium excretion, including kidney diseases (like chronic kidney disease or nephrotic syndrome), certain medications (e.g., diuretics), hormonal imbalances (like hyperaldosteronism), or conditions that alter fluid balance (e.g., heart failure or liver disease). Lifestyle factors like diet (high or low sodium intake) can also influence results.
How can I prepare for this test?
Follow your doctor’s instructions carefully. Avoid special diets or medications unless directed. If you’re on a low-sodium diet, check with your provider first. Drink enough water to produce about 600–800 mL (2–3 cups) of urine daily, but don’t exceed this unless advised. Some tests require fasting, so confirm with your lab or doctor.
Does this test hurt or cause discomfort?
No, this test involves collecting urine over 24 hours—no needles or invasive procedures. The only effort required is consistent urine collection and proper storage. If you have kidney issues or urinary tract problems, let your doctor know to ensure the test is safe and accurate.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy