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24-Hour Urinary Sodium Intake Measurement

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

This test measures how much sodium (a key mineral) you consume and excrete in your urine over a 24-hour period. It helps assess kidney function and balance of fluids and electrolytes.

Quick summary

["This test helps doctors check if your kidneys are working properly or if you’re retaining or losing too much sodium."]

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

Key facts at a glance

LOINC
9088-6
Short code
Sodium intake 1h
Synonyms
Sodium intake 1h
Category
electrolyte
Sample
serum
Container
Red-top tube (SST)
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 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

Your kidneys filter sodium from your blood and release it into your urine. This test helps identify if you’re losing too much sodium (which can cause dehydration or muscle cramps) or retaining too much (which may indicate kidney problems or conditions like heart failure).

How It’s Done

You’ll be given a 24-hour urine collection kit to collect all urine for a full day. You’ll need to urinate into the container every time, including first thing in the morning. The sample is then sent to a lab for analysis.

What to Expect Before the Test

No special preparation is needed, but you should drink enough water to produce urine throughout the day. Avoid using diuretics (like caffeine or certain medications) unless instructed by your doctor.

What to Expect After the Test

After the test, you can return to your normal activities. If you had any side effects (like dizziness or extreme thirst), contact your healthcare provider.

Reference range

Adult: 136-145 mmol/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24h Urinary Sodium

Frequently asked questions

How long does it take to get results?
Results are typically available within 1 to 2 weeks, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
Can I eat or drink normally while collecting urine for this test?
Yes, you can eat and drink normally, but avoid excessive caffeine or alcohol, as they may affect sodium levels. Follow your doctor’s specific instructions for the collection period.
What if I miss collecting urine at night?
If you miss any urine collection, you’ll need to restart the 24-hour period. Some labs may accept partial samples, but it’s best to complete the full collection for accurate results.
  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