Sodium/Creatinine Ratio (FENA)

Specimen:

Collect

  • One SST
  • Random Urine in Sterile Specimen Container

Submit

  • 1 mL (Min:0.5 mL) Serum . Submit Refrigerated. Submit in a Standard Transport Tube.
  • 10 mL (Min:0.5 mL) Random Urine . Submit Refrigerated.

Special Handling

  • See Individual Components for Special Handling and Alternate Sample Types
  • Serum must be collected within 24 hours of urine collection.

Stability

See Individual Components

Methodology

  • Colorimetric

Performed

Mon-Fri

Reported

1-2 Day(s)

CPT Codes

  • 82565
  • 82570
  • 84295
  • 84300

Interpretive Data

Please see report for interpretive data.
Prerenal Intrinsic Renal Postrenal
URINE SODIUM (meq/L) <20 >40 >40
FENa <1% >1% >4%
Prerenal: Anything that causes decreased effective renal perfusion: Hypovolemia, CHF, Renal Artery Stenosis, Sepsis, etc. Remember, contrast-induced nephrology will often look pre-renal.
Intrinsic Renal: ATN, AIN, Glomerulonephritis, etc.
Postrenal: Obstruction (BPH, bladder stone, bilateral ureter obstruction)

Components

  • 1014 - CREATININE, SERUM
  • 1108 - SODIUM,URINE
  • 1026 - SODIUM
  • 2498 - CREATININE, URINE
  • 1086 - FENA
Last Updated: February 6, 2025 @ 10:13 am

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