Specimen Requirements
Title
Urea Nitrogen (BUN), 24 Hour Urine
Specimen Requirement
At the start of the 24 hour collection, discard first morning urine, from that time collect all urine for 24 hours. Record total volume of urine, mix well, then aliquot 10 mL to a screw top container. Indicate total volume of 24 hour urine on aliquot and requisition.
Total volume must be recorded for testing.
Methodology
Spectrophotometry (SP)
Stability
Room temp: 24 hours (collection time), Refrigerated: 7 days, Frozen: 15 months
Reference Range
By Report*
Turnaround
3-4 days, set up Monday-Saturday
Clinical Use
Urea excreted in the urine is the primary method of nitrogen elimination. Conditions associated with increased urine urea nitrogen are hyperthyroidism, high protein diets and post-operative states. Decreased levels are associated with convalescence, liver disease, toxemia and advanced renal disease.
Test Code
UUNMP