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Test Code LAB2599 Whole Blood Potassium - Capillary

Important Note

FDA Guidance Update – iSTAT Capillary Sample Testing

Effective immediately, iSTAT capillary specimens can no longer be used to report results for the following analytes:

• Potassium (K⁺)

• Ionized Calcium (iCa²⁺)

• Lactate

 

Capillary Specimens for K⁺, iCa²⁺, or Lactate must be sent to the Laboratory for testing.

 

Additional Codes

WB K

Notes:

If not analyzed within 30 minutes of draw time, specimen must be tightly capped and transported on ice.  All specimens must have air bubbles expelled and the syringe capped. 

Collection:

Container:  Heparinized Syringe


 
Collection Volume: Heparinized Syringe - 0.4 mL

 

 

iSTAT capillary exception:

  • Collection Tube: Use the No Gel Lithium Heparin Microtainer tube (green bullet tube). Our Day Item# 236225
  • Collection Volume: 400 µL
  • Minimum Volume: 200 µL (the first line on the no-gel bullet tube, clearly marked; see Figure 1).
  • Transport: Send specimens via pneumatic tube station immediately to the ART lab at room temperature. *DO NOT SEND ON ICE*
  • Capillary specimens are a suboptimal sample type for potassium testing due to a higher risk of invitro hemolysis.
  • All capillary specimens submitted for K⁺ testing will be visually inspected for hemolysis. Grossly hemolyzed samples will be rejected.

Stability:

Do not store. Send specimen to lab immediately.

 

Ambient: 30 Minutes

On Ice (preferred): 60 Minutes

Turn Around Time (TAT):

STAT: 10 MINUTES

Test Availability:

24 hrs a day / 7 Days a week

Reference Interval:

Age Reference Range
< 1 Month 3.2 - 5.4 mmol/L
1 Month - < 6 Months 3.5 - 5.6 mmol/L
> 6 Months 3.5 - 5.0 mmol/L

 

Performing Laboratory Section

ART and Shawn Jenkins Hospital:  send to ART OR Lab, 4th floor, Tube Station #55.

 

Main Hospital campus: send to Central Lab Receiving - EH318 University Hospital Extension, Tube Station #99.