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HelpOrder Code CITRA Citrate Excretion, Random, Urine
Ordering Guidance
A timed 24-hour collection is the preferred specimen for measuring and interpreting this urinary analyte. Order CITR / Citrate Excretion, 24 Hour, Urine.
Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children.
Specimen Required
Patient Preparation: Any drug that causes alkalemia or acidemia may be expected to alter citrate excretion and should be avoided, if possible. The patient must avoid laxative use for 24 hours prior to collection.
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 4 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Useful For
Diagnosing risk factors for patients with calcium kidney stones using random urine specimens
Monitoring results of therapy in patients with calcium stones or renal tubular acidosis
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| CITR2 | Citrate Concentration, Random, U | No | Yes |
| CRETR | Creatinine, Random, U | No | Yes |
| RAT10 | Citrate/Creatinine Ratio | No | Yes |
Method Name
Enzymatic
Reporting Name
Citrate Excretion, Random, USpecimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
No established reference values.
Method Description
Citric acid in the presence of zinc (2+) 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). The citric acid concentration in the reaction mixture can be determined by measuring the disappearance of the light-absorbing NADH(Delaney MP, Lamb EJ: Kidney disease. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1309-1310)
Day(s) Performed
Monday through Saturday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82507
82570