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Laboratory Medicine

Laboratory Test Catalogue

Potassium (K)

Test Name

Potassium (K)

Gold Tube Specimen Type / Requirements

Container Type = Gold (SST)

Minimum Volume = 1ml Serum

Tube must fill to at least ½ or greater of its vacuum capacity

Specimen Handling

Collection Instructions: Serum or plasma, free from hemolysis, collected with or without gel separator. For plasma use lithium or ammonium heparin only. Separate serum or plasma from cells within 2 hours of collection

Write your initials, date and time of collection on the collection label.

Stability: Lytes is stable at room temperature for 24 h, refrigerated for 1 week and frozen at -15 to -20°C for 6 months.

Transportation: Transport at room temperature ASAP.

Laboratory Staff Instructions: Separate serum or plasma from cells within 2 hours of collection.

Sample Rejection Criteria: Gross hemolysis and/or Non sufficient Quantity (Not Sufficient Quantity) will be cancelled.

Required Documentation

Turnaround Time (TAT)

45 minutes Trauma/Stat,
2 hours routine

Test Utilization

Reference Value

Potassium: Serum: 3.5-5.0 mmol/L

Potassium Plasma: 3.2-4.8 mmol/L

Critical Results: Serum < 2.5 mmol/L and > 5.7 mmol/L

Test Code



Indirect Potentiometry

Testing Location


Other Information

Last Updated: September 26, 2019