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HelpTest Code LAB1857 Sodium, Fractional Excretion
Useful For
- Assessing kidney function
- Differentiating prerenal disease (decreased renal perfusion) from acute tubular necrosis (ATN) as the cause of acute kidney injury
Profile Information
| Test Code | Test Name | Methodology |
Available Separately |
Always Performed |
|---|---|---|---|---|
| LAB122 | Sodium, plasma or serum | Ion-Selective Electrode | Yes | Yes |
| LAB444 | Sodium, random urine | Ion-Selective Electrode | Yes | Yes |
| LAB383 | Creatinine, plasma or serum | Kinetic Colorimetric (Jaffe) | Yes | Yes |
| LAB384 | Creatinine, random urine | Kinetic Colorimetric (Jaffe) | Yes | Yes |
| N/A | Sodium, Fractional Excretion | Calculation | No | Yes |
Performing Laboratory
Bozeman Health Laboratory Services
Specimen Requirements
Note: Both a urine and serum sample are required
Specimen Type: Plasma or serum
Container/Tube: Light-green top (lithium heparin gel), red top, or gold top
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL
Collection Instructions: Spin down and separate serum/plasma from cells within 2 hours.
Specimen Type: Urine
Container/Tube: Clean container
Specimen Volume: 10 mL
Collection Instructions:
- Collect a random urine collection.
- No preservative.
- Centrifuge specimen before analysis
Specimen Transport Temperature
Plasma or serum: Ambient
Urine: Refrigerated
Specimen Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma or Serum | Ambient | 7 days |
| Refrigerated | 7 days | |
| Frozen | 3 months | |
| Urine | Ambient | 2 hours |
| Refrigerated | 6 days | |
| Frozen | 3 months |
Reference Values
No reference range established
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
82570