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Test Code U Cit Rndm Citrate Excretion, Pediatric, Random, Urine

Reporting Name

Citrate Excretion, Peds, Random, U

Useful For

Diagnosing risk factors for patients with calcium kidney stones.

 

Monitoring results of therapy in patients with calcium stones or renal tubular acidosis.

 

A timed 24-hour urine collection is the preferred specimen for measuring and interpreting this urinary analyte. Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children. Therefore, this random test is offered for children <16 years old.


Specimen Required


Container/Tube: Plastic, 5-mL tube (T465)

Specimen Volume: 4 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Additional Information:

1. A timed 24-hour collection is the preferred specimen for measuring and interpreting this urinary analyte. Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children. Therefore, this random test is offered for children <16 years old.

2. Any drug that causes alkalemia or acidemia may be expected to alter citrate excretion and should be avoided, if possible.


Specimen Type

Urine

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  14 days

Day(s) and Time(s) Performed

Monday through Saturday; 8 a.m.-4 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Enzymatic

Method Description

Citric acid in the presence of Zn(++) at pH 8.2 is catalyzed to oxaloacetate by the enzyme, citrate lyase. Oxaloacetate in the presence of malate dehydrogenase and reduced nicotinamide adenine dinucleotide (NADH) is reduced to malate (II). By measuring the disappearance of the light-absorbing NADH, the citric acid concentration in the reaction mixture can be determined.(Nielsen TT: A method for enzymatic determination of citrate in serum and urine. Scand J Clin Lab Invest 1976;36:513-519)

Reference Values

No established reference values

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82507

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RCITR Citrate Excretion, Peds, Random, U In Process

 

Result ID Test Result Name Result LOINC Value
CITR1 Citrate Concentration, Peds, Random, U 2128-7
CREA9 Creatinine Concentration 2161-8
RATO8 Citrate/Creatinine Ratio 13722-4

Reject Due To

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

NA