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HelpTest Code LAB4878 FENA (Sodium Clearance), Plasma or Serum and Urine
Additional Codes
| Test Name in EPIC | EPIC Test Code | Mnemonic |
|---|---|---|
| FENA | LAB4878 |
FENA |
FENA (Fractional Excretion of Sodium): The fraction of sodium actually excreted by the body relative to the amount filtered by the kidney.
Useful For/Utility
Fractional excretion of sodium is the fraction of sodium excreted by the body relative to the amount filtered by the kidney. FENA is not a test, but rather a calculation based on the concentrations of sodium and creatinine in the blood and urine.
Methodology
| Profile Information: | |
| Creatinine | Sodium |
| Creatinine, Random Urine | Sodium, Random Urine |
Note: Sodium clearance calculation based on the concentrations of sodium and creatinine in the blood and urine.
Ion-Selective Electrode Diluted (Indirect)
Clinical Information
Calculation of FENa:
FENa =
Urine Na Urine Creatinine
Plasma Na + Plasma Creatinine x 100
Plasma Creatinine
Specimen Requirements
Plasma or serum and urine are required. Plasma or serum must be drawn at approximately the same time as urine collection. Specimens drawn within 2 hours either before or after urine collection will be accepted.
Plasma or Serum
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Plasma
Container/Tube: Light-green top (lithium heparin gel)
Specimen Volume: 0.5 mL
Specimen Minimum Volume: 0.2 mL
Collection Instructions:
1. Separate plasma from cells within 2 hours of draw.
2. If plunger filters are used, immediate removal of serum is indicated unless an air gap can be created between the device and specimen.
Additional Information: Label specimen appropriately (plasma).
Alternate:
Specimen Type: Serum
Container/Tube: Serum gel
Specimen Volume: 0.5 mL
Specimen Minimum Volume: 0.2 mL
Collection Instruction:
1. Separate serum from cells within 2 hours of draw.
2. If plunger filters are used, immediate removal of serum is indicated unless an air gap can be created between the device and specimen.
Additional Information: Label specimen appropriately (serum).
Specimen Type: Urine, random
Container/Tube: Aliquot tube
Specimen Volume: 5 mL
Specimen Minimum Volume: 2 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
3. If specimen is cloudy/bloody, spin and separate supernatant.
Additional Information: Label specimen appropriately (urine).
Specimen Transport Temperature
Refrigerate 5 days/Ambient 8 hours OK/Frozen OK
Day(s) Test Set Up
Monday through Sunday
Performing Laboratory
| Minnesota | North Dakota | Wisconsin |
|---|---|---|
| Deer River Hospital | Fargo Hospital | St. Mary's Hospital - Superior |
| Hibbing Clinic | ||
| Moose Lake Hospital | ||
| Northern Pines (Aurora) | ||
| SMDC Clinical Lab (Duluth) | ||
| St. Joseph's Medical Center (Brainerd) | ||
| St. Mary's - Detroit Lakes Hospital | ||
| Virginia Hospital |
Test Classification and CPT Coding
See individual test listings.
Reference Values
<1 % Prerenal
>1 % Intrinsic Renal
>4 % Postrenal
Prerenal: Anything that causes decreased effective renal perfusion: Hypovolemia, CHF, Renal Artery Stenosis, Sepsis, etc.
Intrinsic Renal: Acute Tubular Necrosis, AIN, Glomerulonephritis, etc.
Postrenal: Obstruction (BPH), Bladder Stone, Bilateral Ureter Obstruction.
See individual test listings for analyte reference values.