Collection/Processing Instructions

10 mL aliquot from a well-mixed 24 hour urine collected with 7 g. sulfamic acid.  Indicate the collection time.  The total volume collected must be measured, recorded, and included with the test request.

When only Phosphorus is requested, an acceptable alternative preservative is 20 mL 6N hydrochloric acid. 

If uric acid is also ordered, no preservative is needed but maintain specimen refrigerated during patient collection as well as transport to the receiving facility. 

Receiving facility must prepare two 10 mL aliquots, adjusting pH of phosphorus aliquot to 5 or less using 6N hydrochloric acid (also appropriate for calcium, magnesium, oxalate, and citrate) and the pH of a second (uric acid) aliquot to 7.5-8.5 using 20% sodium hydroxide. 

Alternatively, use Marshfield preservative-containing aliquot tubes which provide automatic pH adjustment.