Urine Phosphorus

Test Code

URPHOS

CPT Codes
84105

Includes

Random Specimen includes Urine Phosphorus. Timed Specimen includes Urine Volume, Hours Collected, Urine Phosphorus, and Phosphorus/Total Volume Ratio.

Preferred Specimen

Random or Timed Urine Specimen

Minimum Volume

1 mL

Instructions

Collect random specimen or timed specimen per orders. For timed specimen, record start and stop time of collection or number of hours. To transfer specimen from large container to smaller container for transport, measure volume first and record on specimen container, along with time. Timed specimens are typically collected for 24 hours, but can be collected for other increments, for example, 4 hours or 12 hours.

This test is measurement of Phosphorus on Urine. For measurement of Phospherous on Plasma or Serum, order PHOS. For measurement of Phosphorus on Body Fluids, order MISP.

Transport Container

24-hour urine container or sterile urine cup

Transport Temperature

Refrigeration

Specimen Stability

3 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Quantity Not Sufficient

Methodology
Colorimetric

Setup Schedule

Monday - Sunday, 8:00 am - 3:00 pm upon receipt

Report Available

Upon completion of analysis

Reference Range

Urine Volume: 800 - 1800 mL/24 hours
Urine Phospherous/Total Volume Ratio: 0.4 - 1.3 g/24 hours

Clinical Significance

Urine Phosphorus measurement is useful for evaluation of hypo- or hyper-phosphatemic states and evaluation of patients with nephrolithiasis.

Approximately 80% of filter phosphorus is reabsorbed by renal proximal tubule cells. The regulation of urinary phosphorus excretion is principally dependent on regulation of proximal tubule phosphorus reabsorption. A variety of factors influence renal tubular phosphate reabsorption, and consequent urine excretion. Factors which increase urinary phosphorus excretion include high phosphorus diet, parathyroid hormone, extracellular volume expansion, low dietary potassium intake and proximal tubule defects (eg, Fanconi Syndrome, X-linked hypophosphatemic Rickets, tumor-induced osteomalacia). Factors which decrease, or are associated with decreases in, urinary phosphorus excretion include low dietary phosphorus intake, insulin, high dietary potassium intake, and decreased intestinal absorption of phosphorus (eg, phosphate-binding antacids, vitamin D deficiency, malabsorption states).

A renal leak of phosphate has also been implicated as contributing to kidney stone formation in some patients.

Interpretation of urinary phosphorus excretion is dependent upon the clinical situation, and should be interpreted in conjunction with the serum phosphorus concentration.

This test is for Phosphorus measurement on Urine. For Phosphorus measurement on Plasma or Serum, order PHOS. For Phosphorus measurement on Body Fluids, order MISP.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.