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Test Code Billings Clinic: 4003 Potassium, Plasma or Serum

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • 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.

Methodology

A-LYTE® Integrated Multisensor Technology (IMT)

Specimen Requirements

Submit only 1 of the following specimens:

Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.

 

Plasma

  • Draw blood in a green-top (lithium heparin) tube(s).
  • Spin down and send 0.5 mL of heparinized plasma frozen.

 

Serum

  • Draw blood in a plain, red-top tube(s) or a serum gel tube(s).
  • Spin down and send 0.5 mL of serum frozen

Storage/Stability

Specimen Type Temperature Time
Plasma, Serum Refrigerated 7 days
  Frozen (preferred) 1 month

 

Reject Due To

  • Hemolyzed samples

Reference Values

0 - 1 month:  3.7 - 5.9 mEq/L

1 month - 1 year:  4.1 - 5.3 mEq/L

1 - 17 years:  3.4 - 4.7 mEq/L

> 17 years:  3.5 - 5.1 mEq/L
 

Call-back values:  <3.0 mEq/L or >6.0 mEq/L

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

84132 - Potassium, blood

LOINC Code Information

Reporting Name LOINC Code
Potassium 2823-3

 

Interferences

  • Avoid hemolyzed samples for potassium. Hemolyzed samples may give incorrect elevated potassium. Intracellular potassium concentration is 30–50 times greater than that of extracellular serum or plasma.
  • Samples exposed to benzalkonium salts present in certain blood catheter devices will cause falsely elevated potassium measurements.
  • Iron at 1 g/dL increases the potassium result in serum/plasma at 2.69 mmol/L (2.69 mEq/L) by 17% and 4.54 mmol/L (4.54 mEq/L) by 11%.