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HelpTest Code RPHOC Phosphorus, Random, Urine
Specimen Required
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.
Useful For
Evaluation of hypo- or hyperphosphatemic states
Evaluation of patients with nephrolithiasis
Method Name
Molybdic Acid
Reporting Name
Phosphorus, Random, USpecimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 30 days | ||
| Ambient | 7 days |
Reference Values
No established reference values
Random urine phosphorus may be interpreted in conjunction with serum phosphorus, using both values to calculate fractional excretion of chloride.
The calculation for fractional excretion (FE) of phosphorus is
FE(P)= ([P(urine) X Creat(serum)]/[P(serum) X Creat(urine)])X100
Interpretation
Interpretation of urinary phosphorous excretion is dependent upon the clinical situation and should be interpreted in conjunction with the serum phosphorous concentration.
Clinical Reference
1. 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; 2018:1280-1283
2. Matos V, van Melle G, Boulat O et al: Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr. 1997;131:252-257
3. Agarwal R, Knochel JP: Hypophosphatemia and hyperphosphatemia. In: Brenner BM, ed. The Kidney. 6th ed. WB Saunders Company; 2000:1071-1125
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84105
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RPHOC | Phosphorus, Random, U | 2778-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| RPHOC | Phosphorus, Random, U | 2778-9 |
Day(s) Performed
Monday through Sunday