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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