Test Code LAB4290 UREA REDUCTION RATIO
Specimen Type
Preferred Sample: Lithium Heparin Plasma (Mint Green Top, Dark Green Top)
Alternative Sample: Serum (SST, Gold, Corvac, Tiger, Red Top Tube)
Collection Instructions
Draw Pre-dialysis specimen at the start of dialysis and the Post-dialysis specimen at the end of dialysis. Clearly label each sample as either PRE or POST and include the collection time on the label.
Specimen Volume
2 mL
Minimum Volume
0.2 mL
Turnaround Time
STAT: within 1 hour of both specimens being received
Routine: 4 hours
Test Schedule
Daily
Sample Stability
Room Temp: 7 days
Refrigerated: 7 days
Frozen: 12 months
Method
Colorimetric
Reference Ranges
BUN, Pre: 7 – 23 mg/dL
BUN, Post: 7 – 23 mg/dL Urea Reduction:
Reference Range not established.
No fixed number can be said to represent an adequate dialysis. Some groups advising on national standards have recommended a minimum URR of 65%
Synonyms
URR; BUN PRE and POST
Test Components
BUN, Pre; BUN, Post; Urea Reduction
CPT Codes
84520 x2
Rejection Criteria
specimens without a clear PRE or POST designation will not be accepted