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Test Code AMMO Ammonium, 24 Hour, Urine

Useful For

Diagnosis of the cause of acidosis

 

Diagnosis and treatment of kidney stones

Method Name

Enzymatic

Reporting Name

Ammonium, 24 Hr, U

Specimen Type

Urine


Necessary Information


24-Hour volume (in milliliters) is required.



Specimen Required


Supplies:

-Sarstedt 5 mL Aliquot Tube (T914)

-Diazolidinyl Urea (Germall) 5.0 mL (T822)

Container/Tube: Plastic vial

Specimen Volume: 4 mL

Collection Instructions:

1. Add 5 mL of diazolidinyl urea (Germall) as preservative at start of collection or refrigerate specimen during and after collection.

2. Collect urine for 24 hours.

3. Aliquot urine into plastic vial.

4. Specimens with pH >8 may indicate bacterial contamination and testing will be cancelled. Do not attempt to adjust pH as it will adversely affect results.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Reference Values

15-56 mmol/24 hour

Reference values have not been established for patients <18 years and >77 years of age.

Reference values apply to 24 hour collections.

Interpretation

If a patient has acidosis and the amount of ammonium in the urine is low, this is suggestive of a renal tubular acidosis.

 

If the amount of ammonium is high, this suggests that the kidneys are working normally and that there are other losses of bicarbonate in the body. Typically this implies gastrointestinal losses.

Clinical Reference

1. Peonides A, Levin B, Young W: The renal excretion of hydrogen ions in infants and children. Arch Dis Child. 1965 Feb;40(209):33-39

2. Kamel KS, Briceno LF, Sanchez MI, et al: A new classification for renal defects in net acid excretion. Am J Kidney Dis. 1997 Jan;29(1):136-146

3. Madison LL, Seldin DW: Ammonia excretion and renal enzymatic adaptation in human subjects, as disclosed by administration of precursor amino acids. J Clin Invest .1958 Nov;37(11):1615-1627

4. Coe FL, Evan A, Worcester E: Pathophysiology-based treatment of idiopathic calcium kidney stones. Clin J Am Soc Nephrol. 2011 Aug;6(8):2083-2092

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 to 2 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82140

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AMMO Ammonium, 24 Hr, U 25308-8

 

Result ID Test Result Name Result LOINC Value
AM24 Ammonium, 24 Hr, U 25308-8
TM25 Collection Duration 13362-9
VL91 Urine Volume 3167-4

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.