32148:FRACTIONAL EXCRETION OF SODIUM

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32148:FRACTIONAL EXCRETION OF SODIUM
Alias Names: FENa
Methodology: Indirect Potentiometry
Edit Date: 6/11/2010
Performed: Daily
Released: Same day as tested
CPT Code: 82565 / 82570 / 84295 / 84300
Specimen Collection Details
Collection: Two specimens required: One 7.5 mL serum separtor tube (SST), [also acceptable: One heparin plasma separator tube (PST)], and a single urine in a sterile plastic container. Refrigerate. NOTE: Specimens for testing both blood sodium and creatinine and random urine sodium and creatinine must be collected simultaneously. Serum and urine specimens can be collected within 24 hours of each other.
Handling: Centrifuge and separate serum or plasma from cells within 3 hours of collection and transport in original tube. Refrigerate.
Standard Volume: 2 mL serum or plasma and 25 mL urine.
Minimum Volume: 0.5 mL serum or plasma and 5 mL urine.
Transport: Refrigerated.
Rejection Criteria: Tubes other than those specified; urine and serum collected more than 24 hours apart.

<1% Prerenal disease
1-2% Intermediate
>2% Acute Tubular Necrosis (ATN)