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Test Code 158 Sodium and Potassium

Additional Codes

MLAB: NAK

PowerChart: Sodium and Potassium Level

Epic: LAB4884 Sodium and Potassium Level

MA Cerner: Sodium and Potassium.

Test Method

Sodium:

  • UCL: Ion-Selective Electrode Potentiometry; Beckman & I-Stat
  • MA: Indirect Sample Sensing with IMT; Siemens

Potassium:

  • Mercy DBQ and Finley: Ion Specific Electrode; Beckman
  • Mercy DV and MQMA: Ion Selective Electrode Poteniometry; iSTAT
  • MA: Indirect Sample Sensing with IMT; Siemens

Specimen Requirement

0.5 mL serum or plasma is required.

Additional Specimen Collection Information

Collect blood in a lithium heparin, green-top or red-top tube. PST and SST (gel tubes) are acceptable. Serum or plasma should be separated from contact with the cells within 2 hours of collection. Specimens not centrifuged within 4 hours of collection may be rejected. Refrigerate the specimen if unable to assay within 8 hours of collection. Hemolyzed specimens are not acceptable. Samples with ≥3+ lipemia must be cleared prior to analysis.

Performance

Testing is performed Monday through Sunday.

Routine orders: Typically completed within 4 hours after the specimen arrives at the testing site.

Expedite: Typically completed within 1 hour after the specimen arrives at the testing site.

STAT: Typically completed within 30 minutes after the specimen arrives at the testing site.

Reference Values

Sodium: 135-145 meq/L

  • Critical Values:
    • Low: <120 meq/L
    • High: >160 meq/L

Potassium: 3.5-5.0 meq/L

  • Critical Values:
    • Low: <3.0 meq/L
    • High: >6.0 meq/L

CPT Code Information

84295 Chemistry: Sodium, serum, plasma or whole blood

84132 Chemistry: Potassium, serum, plasma or whole blood

Useful For

Sodium assays are important in assessing acid-base balance, water balance, water intoxication, and dehydration.

Evaluation of electrolyte balance, cardiac arrhythmia, muscular weakness, hepatic encephalopathy, and renal failure

Potassium should be monitored during treatment of many conditions but especially in diabetic ketoacidosis and any intravenous therapy for fluid replacement.

LOINC Code Information

2951-2 Sodium [Moles/Volume] In Serum Or Plasma

2823-3 Potassium [Moles/Volume] In Serum Or Plasma