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Laboratory: Clinical Biochemistry  (POC (Point of Care) TEST)
Test Name:
Sodium - epoc - (B)
Test Code: NAB
Clinical Information:
Description: Sodium is the primary extracellular cation and functions to maintain fluid distribution and osmotic pressure. Measurement of sodium is important for the assessment of acid-base balance, water balance and hydration. An elevated anion gap strongly suggests the presence of metabolic acidosis [Anion gap = Na - (Cl + TCO2)].

 

The whole blood anion gap may be requested as part of the epoc test menu.

 

Collection Devices:
Capillary specimens must be collected in a balanced heparin capillary tube (FULL collection), capped, mixed, and tested within 5 minutes of collection.
Specimen Required:
Whole Blood: 4.0 mL
Pediatric Whole Blood: 0.1 mL

Collection Information: Evacuated blood tubes must be FULL to maintain specimen stability. Specimens must remain capped until tested to avoid contamination with air.

 

Rejection criteria: clots, insufficient volume, leaking specimens, and specimens not received within 30 minutes of collection.

 

Capillary samples must be tested at the bedside, within 5 minutes.

Specimen Stability:

 

Ambient: 30 minutes (Vacutainer, syringe); 5 minutes (capillary)

Refrigerated: DO NOT REFRIGERATE

Frozen: DO NOT FREEZE

Do not submit specimens on ice.

Referral:

Only available at sites which perform epoc testing on-site.
Requisition:
Reference Values:
Reference Intervals: 138-146 mmol/L

Critical Values: <120 mmol/L

                           >160 mmol/L

Method of Analysis: Potentiometry – Direct Ion-Selective Electrode

Siemens epoc® Blood Analysis System, BGEM test card

Availability:
Daily or Stat
See Also:
More Information:
Interpretation & Assay Interferences: See attached epoc assay interference document