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Test Code U24 Na Urine 24 Hour, Sodium Level

Patient Preparation

No special patient preparation required

Special Collection Instructions

Specimen must be received with the following information included:

  • Total volume of collection
  • Start date and time
  • Stop date and time

Collection Method

24 hour urine collection

Minimum Volume

  • Adults: 0.5 ml
  • Pediatric: 0.3 ml

Container

24 hour urine container

Preferred Specimen

24 hour urine container

Acceptable Specimens

24 hour urine container

Reference or Target Ranges

42 – 220 mmol/24 hour period

Reportable Units

mmol/24 hour period

Critical Value

Not defined for this assay

Reasons for Rejection

Hemolysis Threshold 1000 mg/dL
Icterus Threshold 60 mg/dL
Lipemia Threshold 2000 mg/dL
Other QNS, contaminated, improperly Labeled, improper specimen type, collection information not provided

Specimen Stability

Ambient 14 days
Refrigerated (4°C to 8°C) 14 days
Frozen(-40°C to 0°C) 2 years

Performance Information

Days and Time Performed 24/7
Expected Turn Around Time Stat: 1 hour
Routine: 4 hours
Stat Availabilty Yes
Performing Bench UH Chemistry, WCH Chemistry
Methodology/Method Description Roche Cobas – Ion-selective Electrode (ISE)

Additional Information/Important Notes

The laboratory computer system cannot extrapolate a 24 hour urine result with data from a timed urine sample that is not 24 hours. If a timed urine specimen is submitted that is not 24 hours and the physician insists that it be tested, the order cannot be resulted as a 24 hour urine. Cancel the 24 hour urine order and reorder the test as for a random urine. Enter the sodium result in mmol/L and add the following comment: “This urine specimen was collected over a period of _ hours with a total volume of _ mL. Since the collection period is not 24 hours, automatic extrapolation to 24 hour reports is not available. Clinical correlation and/or manual calculation of extrapolated 24 hour urine excretion levels is required.” (Enter the collection period in the first blank and the total volume in mL in the second blank.)

CPT Codes

81050;84300