Geisinger Medical Laboratories/Geisinger Proven Diagnostics Test Catalog

Order Display Name: Geisinger Epic Procedure Code Or ID CPT Code:  

SODIUM FRACT EXCRET

ORDERING INFORMATION:
Geisinger Epic Procedure Code: LAB3469         Geisinger Epic ID: 23482

SPECIMEN COLLECTION
Specimen type:
Serum OR plasma* AND random urine
Preferred collection container:
Specimen required:
2 mL aliquot serum or plasma; 5 mL urine. Collection of serum and urine specimens must be within 8 hours.
Special notes:
*Lithium heparin plasma is acceptable from in-house collection.

SPECIMEN PROCESSING
Specimen processing instructions:
Allow serum to clot. Centrifuge to separate serum or plasma. 
Transport temperature:
Refrigerated.
Specimen stability:
See individual member listing.
Rejection criteria:
Serum (or plasma) and urine specimens collected more than 8 hours apart are not acceptable.

TEST DETAILS
Interpretation guide:
Fractional excretion of sodium (FeNa) should only be used in the setting of AKI.

For patients with AKI:
<1% suggestive of prerenal disease such as true volume depletion or decreased effective circulating volume (heart failure, cirrhosis). Can also be seen in acute glomerulonephritis, contrast nephropathy, or pigment nephropathy.
1-2% non-diagnostic
>2% suggestive of ATN

Considerations:
FeNa can be falsely elevated in patients with CKD or on diuretics. For patients on diuretics, the fractional excretion of urea (FEUrea) is preferred.
CPT code(s):
84295, 82565, 82570, 84300
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.  The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.
Test includes:
Urine sodium, urine creatinine, serum sodium, serum creatinine.
Methodology:
Potentiometric
Spectrophotometric (Colorimetric)
Synonyms:
SODIUM FRACTIONAL EXCRETION
Clinical significance:
This test can aid in the differentiation of prerenal disease and acute tubular necrosis (ATN).
Doctoral Director(s:)
Hoi-Ying Elsie Yu, PhD, DABCC
Sheng-Ying (Margaret) Lo, PhD, DABCC    
Review Date: 12/24/2020

Performing Locations

Geisinger Medical Center

Performing laboratory: Automated Chemistry
Technical Lead: Mariana Moyer, Jared Shepherd
Frequency: Daily, Monday - Sunday
Performed stat? No
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