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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
Chemistry-
St. Joseph's Medical Center Lab
Hibbing Clinic Lab, SMDC Clinical Lab, St. Mary's Superior Hospital Lab
Fargo Hospital Lab, Fosston Hospital Lab, St. Mary's Detroit Lake Hospital Lab
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.