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Amino Acid Nitrogen, 24-Hour Urine — Mass Rate

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

Measures the amount of amino acid nitrogen excreted in urine over 24 hours, which can help assess protein metabolism and kidney handling.

Quick summary

["This test estimates how much amino acid nitrogen your body releases in urine over one day."]

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

Key facts at a glance

LOINC
1785-5
Short code
A-AA Nitrogen 24h Ur-mRate
Synonyms
A-AA Nitrogen 24h Ur-mRate
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This 24-hour urine test measures the total amount of amino acid nitrogen excreted in your urine. It provides an estimate of amino acid breakdown and how your kidneys handle these nitrogen-containing substances.

Why might I need this test?

A clinician may order this test to evaluate protein metabolism, nutritional status, or unusual urinary loss of amino acids. It may also be used alongside other tests when assessing kidney function.

How is the test performed?

You collect all urine produced during a full 24-hour period. The laboratory measures the total urine volume and the amount of amino acid nitrogen, then calculates the amount excreted per unit of time.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory, including the exact start and stop times. Keep the container refrigerated if instructed, record any missed collections, and tell your clinician about major changes in diet, illness, or supplements.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Amino Acid Nitrogen

Frequently asked questions

Is this the same as a urine amino acid profile?
No. This test measures total amino acid nitrogen in a 24-hour urine collection rather than identifying and quantifying each amino acid separately.
Why does the collection need to last 24 hours?
Urine excretion varies throughout the day. Collecting all urine for 24 hours gives a more representative measurement of the total amount released by the body.
Do I need to change my diet before the test?
Do not make major dietary changes unless your clinician specifically directs you. Inform the care team about unusual protein intake, supplements, illness, and any urine samples that were missed.
  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