Specimen Requirements

Container/Tube:

Preferred: Green-top (lithium heparin) tube.  Hemolyzed specimen or sodium heparin tube is not acceptable.

Acceptable: Gold-top serum gel tube or plain red-top tube

Specimen Volume: 0.2 mL of plasma or serum

Stability: Samples can be kept at 2 – 8°C and analyzed within 3 days. For longer storage, samples may be frozen at -20°C or colder indefinitely.

Collection Instructions: For glucose testing a fasting specimen is preferred. Tube should be kept capped as much as possible.

Note: 1. Elevated platelets can cause a falsely elevated serum potassium level because of the release of potassium during clotting process. Specimens from patients with elevated platelet counts must be drawn in a heparinized plasma tube.