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22855 Renal Failure Indices

Renal Failure Indices
Test Code: RI
Synonyms/Keywords
​Fractional Excretion of Sodium, Renal Failure Index, RFI​
Test Components
Urine Creatinine and Sodium
Blood Creatinine and Sodium​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No
Urine​
Urine without preservative
 Urine with 0.5 g sulfamic acid, 6N HCL, 33% acetic acid, or boric acid
10 mL​
0.5 mL ​
 ​
​Plasma/Serum
(*See Collection Instructions)
 Lithium-heparin Plasma Separator Tube (PST)
 ​Serum Separator Tube (SST), Lithium or Sodium-Heparinized Green Top Tube (GTT), or Red Top Tube (RTT)
 ​1​ mL ​0.3 mL ​
Collection Processing Instructions
*If there is no other blood creatinine or sodium order on the same encounter within 8 hours of urine collection, a blood order of RI-BLD (Renal Indices-Blood) will be reflexed when the urine order is completely activated and should be drawn upon receipt of urine. 

Note: Blood specimens are acceptable no earlier than 8 hours prior to the start of the urine collection or no later than 8 hours after the collection ends.

Specimen Stability Information

​​Specimen Type
​Temperature
​Time
​Urine - No Preservative
​Refrigerate
​4 days
​Urine - W/Preservative
​Refrigerate
​7 days
​Plasma/Serum​
​		​Ambient
​5 days
​Refrigerate
​7 days

Rejection Criteria
​​If either the blood or urine specimen is not available, the test cannot be performed
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours
 Modified Jaffe Kinetic Fixed Assay & ISE/Beckman Coulter AU
Reference Range Information
Performing Location Reference Range
Marshfield​ <1 implies pre-renal azotemia
Values >1 may indicate acute renal failure​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84300   ​ ​ ​  Sodium, urine  ​ ​
82570  ​ ​ ​ Creatinine, other source​ ​
84295 ​ ​ ​ Sodium, serum ​ ​If needed
82565​ ​ ​  Creatinine, blood ​ ​If needed
Synonyms/Keywords
​Fractional Excretion of Sodium, Renal Failure Index, RFI​
Test Components
Urine Creatinine and Sodium
Blood Creatinine and Sodium​
Ordering Applications
Ordering Application Description
4medica
 ​Renal Failure Indices
​Cerner ​Renal Failure Index
Renal Failure Indices
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No
Urine​
Urine without preservative
 Urine with 0.5 g sulfamic acid, 6N HCL, 33% acetic acid, or boric acid
10 mL​
0.5 mL ​
 ​
​Plasma/Serum
(*See Collection Instructions)
 Lithium-heparin Plasma Separator Tube (PST)
 ​Serum Separator Tube (SST), Lithium or Sodium-Heparinized Green Top Tube (GTT), or Red Top Tube (RTT)
 ​1​ mL ​0.3 mL ​
Collection Processing
*If there is no other blood creatinine or sodium order on the same encounter within 8 hours of urine collection, a blood order of RI-BLD (Renal Indices-Blood) will be reflexed when the urine order is completely activated and should be drawn upon receipt of urine. 

Note: Blood specimens are acceptable no earlier than 8 hours prior to the start of the urine collection or no later than 8 hours after the collection ends.

Specimen Stability Information

​​Specimen Type
​Temperature
​Time
​Urine - No Preservative
​Refrigerate
​4 days
​Urine - W/Preservative
​Refrigerate
​7 days
​Plasma/Serum​
​		​Ambient
​5 days
​Refrigerate
​7 days

Rejection Criteria
​​If either the blood or urine specimen is not available, the test cannot be performed
Test Components
Urine Creatinine and Sodium
Blood Creatinine and Sodium​
Reference Range Information
Performing Location Reference Range
Marshfield​ <1 implies pre-renal azotemia
Values >1 may indicate acute renal failure​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours
 Modified Jaffe Kinetic Fixed Assay & ISE/Beckman Coulter AU
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84300   ​ ​ ​  Sodium, urine  ​ ​
82570  ​ ​ ​ Creatinine, other source​ ​
84295 ​ ​ ​ Sodium, serum ​ ​If needed
82565​ ​ ​  Creatinine, blood ​ ​If needed
For most current information refer to the Marshfield Laboratory online reference manual.