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Epic Test Code LAB114 Potassium: Serum/Plasma

Performing Location(s)

BMC,CRH,LFH,HRK,OCH,FTT,FOX,FCC

Specimen Type

Serum or Plasma

Preferred Container

Gold or Red top tube

Alternate Container

Green top tube

Blood Tube Draw Volume

Min 50% draw volume  

Minimum Volume to Submit for Testing

0.5 mL Serum or Plasma

  • Multiple test can be performed from this volume. For question please contact the lab at 547-3975.  

Storage Requirements

Sample tubes should be centrifuged within 2 hours of collection 

Gold tops are stable in original tubes for 7 days DO NOT ALIQUOT

Aliquot Red tops

See Causes of Rejection for temperature requirements.

 

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Transportation Needs

 Deliver specimen to laboratory within 1 hour of collection if unspun. If not possible see "storage Requirements". 

Causes for Rejection

Mislabeled or unlabeled specimen
Less than 50% draw for Vacutainer tubes
> 7 day Refrigerated
> 24 hours Room Temp

Hemolysis > 70 mg/dL HgB
Lipemia > 500 mg/dL Trig
Bilirubin > 40 mg/dL Bili

Reference Values

Population Units Reference Range High Critical Value Low Critical Value
All Populations (Serum) mmol/L 3.5-5.1 >6.0 <2.8
All Populations (Plasma) mmol/L 3.4-4.5 >6.0 <2.8

 

Additional Information

Specimen tubes should be centrifuged unopened and the serum/plasma should be separated within two hours after venipuncture, as prolonged contact with red cells will cause elevated K+ results

Limitations

Samples exposed to Benzalkonium salts present in certain blood catheter devices will cause falsely elevated sodium and potassium measurements.

Citrate at a test concentration of 52.9 mmol/L decreases sodium by 38 mmol/L, decreases potassium be 0.6 mmol/L and increases chloride by 57 mmol/L.

Specimen hemolysis will elevate serum potassium.

Capillary collected blood may differ from venous due to contamination from hemolysis or interstitial fluid.

Days of Analysis

All

Available STAT

Yes

Methodology

Beckman AU/Dx Series

CPT Code

84132

Last Updated

26-OCT-24 MS