Clinical Lab Handbook

Preferred Specimen: Submit an entire 24-hour urine collection in a urine container. No preservative.

Alternate Specimen: Random Urine

Note: 1. Starting and ending times of collection are required.

This procedure provides instructions for quantitatively measuring phosphorus concentration in urine using VITROS PHOS slides. Phosphorus in the form of inorganic and organic phosphate is an important and widely distributed element in the human body. Urinary phosphate varies with age, muscle mass, renal function, PTH, the time of day, and other factors. Urinary excretion varies widely with diet and is essentially equivalent to dietary intake. The kidneys excrete excess phosphorus in the urine to maintain plasma concentrations within optimal levels or to help elevate the plasma calcium level when it falls below normal.

Monday through Sunday

81050-Urine timed measurement

84105-Phosphorus