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Test Code LAB5567 Electrolytes Panel, Whole Blood

Performing Laboratory

St. Louis Children's Hospital Laboratory  - Core Lab

Specimen Requirements

NOTE: This test includes analysis of: Sodium WB; Postassium WB; Chloride WB; CO2 Totl (carbon dioxide) and Anion Gap

Patient Preparation: None

Collection Container/Tube:

Preferred: Air-tight balanced heparinized blood gas syringe

Acceptable: Heparinized Capillary blood gas tube or green microtainer

Submission Container/Tube: May not be received from outside facility

Specimen Collection Volume: 1.0 mL (minimum 0.3 mL)

Special Instructions: Mix well and send to lab immediately. If collecting in capillary blood gas tube be sure to add flea to mix.

 

Sample Rejection

Mislabled or unlabeled specimens 

Clotted specimens

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 30 minutes from receipt in lab

Reference Values

Reference Interval: 

Potassium (all ages):       3.3-4.9 mmol/L                                                
Sodium (all ages): 135-145 mmol/L                                                                   
Chloride  
     <18 years: 100-114 mmol/L
     ≥ 18 years: 97-110 mmol/L
CO2 Totl (all ages): 20-30 mmol/L

Critical Value: 

Poassium:  
     <1 year: <2.5 mmol/L  OR  >7.0 mmol/L                                                  
     ≥ 1 year: <2.5 mmol/L  OR  >6.5 mmol/L
Sodium (all ages): <120 mmol/L  OR  >160 mmol/L
Chloride (all ages): ≤ 75 mmol/L  OR  >130 mmol/L
CO2 Totl (all ages): <10 mmol/L

Critical test esults will be called back automatically initially and every 24 hours thereafter.

 

Methodology

Ion-Selective Electrode (ISE)

Limitations

  • Unable to access hemolysis in whole blood specimens.
  • In vitro hemolysis causes falsely elevated potassium

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: DO NOT SPIN. give specimen directly to blood gas bench

Processed Volume: 1.0 (minimum 0.3 mL) whole blood

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 2 hours
Plasma/Serum (processed) Refrigerated      not acceptable  
  Ambient  not acceptable
  Frozen  not acceptable  

 

Test Classification and CPT Code

Potassium: 84132

Sodium: 84298

Chloride: 82435

LOINC

Potassium WB: 2823-3

Sodium WB: 2951-2

Chloride WB: 2072-0

CO2 Totl WB: 20565-8

Last Reviewed

07/2025